TUMOURS[2]
Definition--Etiology--General characters of innocent and malignant
tumours. CLASSIFICATION OF TUMOURS: I. Connective-tissue tumours:
(1) _Innocent_: _Lipoma_, _Xanthoma_, _Chondroma_, _Osteoma_,
_Odontoma_, _Fibroma_, _Myxoma_, _Endothelioma_, etc.; (2)
_Malignant_: _Sarcoma_--II. Epithelial tumours: (1) _Innocent_:
_Papilloma_, _Adenoma_, _Cystic Adenoma_; (2) _Malignant_:
_Epithelioma_, _Glandular Cancer_, _Rodent Cancer_, _Melanotic
Cancer_--III. Dermoids--IV. Teratoma. Cysts: _Retention_,
_Exudation_, _Implantation_, _Parasitic_, _Lymphatic or Serous_.
Ganglion.
[2] For the histology of tumours the reader is referred to a text-book
of pathology.
A tumour or neoplasm is a localised swelling composed of newly formed
tissue which fulfils no physiological function. Tumours increase in size
quite independently of the growth of the body, and there is no natural
termination to their growth. They are to be distinguished from such
over-growths as are of the nature of simple hypertrophy or local
giantism, and also from inflammatory swellings, which usually develop
under the influence of a definite cause, have a natural termination, and
tend to disappear when the cause ceases to act.
The _etiology of tumours_ is imperfectly understood. Various factors,
acting either singly or in combination, may be concerned in their
development. Certain tumours, for example, are the result of some
congenital malformation of the particular tissue from which they take
origin. This would appear to be the case in many tumours of blood
vessels (angioma), of cartilage (chondroma), of bone (osteoma), and of
secreting gland tissue (adenoma). The theory that tumours originate from
fœtal residues or "rests," is associated with the name of Cohnheim.
These rests are supposed to be undifferentiated embryonic cells which
remain embedded amongst fully formed tissue elements, and lie dormant
until they are excited into active growth and give rise to a tumour.
This mode of origin is illustrated by the development of dermoids from
sequestrated portions of epidermis.
Among the local factors concerned in the development of tumours,
reference must be made to the influence of irritation. This is probably
an important agent in the causation of many of the tumours met with in
the skin and in mucous membranes--for example, cancer of the skin, of
the lip, and of the tongue. The part played by injury is doubtful. It
not infrequently happens that the development of a tumour is preceded by
an injury of the part in which it grows, but it does not necessarily
follow that the injury and the tumour are related as cause and effect.
It is possible that an injury may stimulate into active growth
undifferentiated tissue elements or "rests," and so determine the growth
of a tumour, or that it may alter the characters of a tumour which
already exists, causing it to grow more rapidly.
The popular belief that there is some constitutional peculiarity
concerned in the causation of tumours is largely based on the fact that
certain forms of new growth--for example, cancer--are known to occur
with undue frequency in certain families. The same influence is more
striking in the case of certain innocent tumours--particularly multiple
osteomas and lipomas--which are hereditary in the same sense as
supernumerary or webbed fingers, and appear in members of the same
family through several generations.
INNOCENT AND MALIGNANT TUMOURS
For clinical purposes, tumours are arbitrarily divided into two
classes--the innocent and the malignant. The outstanding difference
between them is, that while the evil effects of innocent tumours are
entirely local and depend for their severity on the environment of the
growth, malignant tumours wherever situated, in addition to producing
similar local effects, injure the general health and ultimately cause
death.
_Innocent_, benign, or simple tumours present a close structural
resemblance to the normal tissues of the body. They grow slowly, and are
usually definitely circumscribed by a fibrous capsule, from which they
are easily enucleated, and they do not tend to recur after removal. In
their growth they merely push aside and compress adjacent parts, and
they present no tendency to ulcerate and bleed unless the overlying skin
or mucous membrane is injured. Although usually solitary, some are
multiple from the outset--for example, fatty, fibrous, and bony tumours,
warts, and fibroid tumours of the uterus. They produce no constitutional
disturbance. They only threaten life when growing in the vicinity of
vital organs, and then only in virtue of their situation--for example,
death may result from an innocent tumour in the air-passage causing
suffocation, in the intestine causing obstruction of the bowels, or in
the vertebral canal causing pressure on the spinal medulla.
_Malignant tumours_ usually show a marked departure from the structure
and arrangement of the normal tissues of the body. Although the cells of
which they are composed are derived from normal tissue cells, they tend
to take on a lower, more vegetative form; they may be regarded as
parasites living at the expense of the organism, multiplying
indefinitely and destroying everything with which they come in contact.
Malignant tumours grow more rapidly than innocent tumours, and tend to
infiltrate their surroundings by sending out prolongations or offshoots;
they are therefore liable to recur after an operation which is
restricted to the removal of the main tumour. They are not encapsulated,
although they may appear to be circumscribed by condensation of the
surrounding tissues; they are rarely multiple at the outset, but show a
marked tendency to spread to other parts of the body. Fragments of the
parent tumour may become separated and be carried off in the lymph or
blood-stream and deposited in other parts of the body, where they give
rise to secondary growths. Malignant tumours tend to invade and destroy
the overlying skin or mucous membrane, and thus give rise to bleeding
ulcers; if the tumour tissue protrudes through the gap in the skin, it
is said to _fungate_. In course of time they give rise to a condition of
ill-health or _cachexia_, the patient becoming pale, sallow, feverish,
and emaciated, probably as a result of chronic poisoning from the
absorption of toxic products from the tumour. They ultimately destroy
life, it may be by their local effects, such as ulceration and
hæmorrhage, by favouring the entrance of septic infection, by
interfering with the function of organs which are essential to life, by
cachexia, or by a combination of these effects.
The situation of a malignant tumour exercises considerable influence on
the rapidity, as well as on the mode, in which it causes death. Some
cancers, such as that known as "rodent," show malignant features which
are entirely local, while others, such as melanotic cancer, exhibit a
malignancy characterised by rapid generalisation of growths throughout
the body. Tumours that are structurally alike may show variations in
malignancy, according to their situation and to the age of the patient,
as well as to other factors which are as yet unknown.
In attempting to arrive at a conclusion as to the innocence or
malignancy of any tumour, too much reliance must not be placed on its
histological features; its situation, rate of growth, and other clinical
features must also be taken into consideration. It cannot be too
emphatically stated that there is no hard-and-fast line between innocent
and malignant growths; there is an indefinite transition from one to the
other. The possibility of the transformation of a benign into a
malignant tumour must be admitted. Such a transformation implies a
change in the structure of the growth, and has been observed especially
in fibrous and cartilaginous tumours, in tumours of the thyreoid gland,
and in uterine fibroids. The alteration in character may take place
under the influence of injury, prolonged or repeated irritation,
incomplete removal of the benign tumour by operation, or the altered
physiological conditions of the tissues which attend upon advancing
years.
After a tumour has been removed by operation it should as a routine
measure be subjected to microscopical examination; the results are often
instructive and sometimes other than what was expected.
#Varieties of Tumours.#--In the following description, tumours are
classified on an anatomical basis, taking in order first the
connective-tissue group and subsequently those that originate in
epithelium.
INNOCENT CONNECTIVE-TISSUE TUMOURS
#Lipoma.#--A lipoma is composed of fat resembling that normally present
in the body. The commonest variety is the _subcutaneous lipoma_, which
grows from the subcutaneous fat, and forms a soft, irregularly lobulated
tumour (Fig. 45). The fat is arranged in lobules separated by
connective-tissue septa, which are continuous with the capsule
surrounding the tumour and with the overlying skin, which becomes
dimpled or puckered when an attempt is made to pinch it up. As the fat
is almost fluid at the body temperature, fluctuation can usually be
detected. These tumours vary greatly in size, occur at all ages, grow
slowly, and, while generally solitary, are sometimes multiple. They are
most commonly met with on the shoulder, buttock, or back. In certain
situations, such as the thigh and perineum, they tend to become
pedunculated (Fig. 46).
A fatty tumour is to be diagnosed from a cold abscess and from a cyst.
The distinguishing features of the lipoma are the tacking down and
dimpling of the overlying skin, the lobulation of the tumour, which is
recognised when it is pressed upon with the flat of the hand, and, more
reliable than either of these, the mobility, the tumour slipping away
when pressed upon at its margin.
[Illustration: FIG. 45.--Subcutaneous Lipoma showing lobulation.]
The prognosis is more favourable than in any other tumour as it never
changes its characters; the only reasons for its removal by operation
are its unsightliness and its probable increase in size in the course of
years. The operation consists in dividing the skin and capsule over the
tumour and shelling it out. Care must be taken that none of the outlying
lobules are left behind. If the overlying skin is damaged or closely
adherent, it should be removed along with the tumour.
[Illustration: FIG. 46.--Pedunculated Lipoma of Buttock of forty years'
duration in a woman æt. 68.]
_Multiple subcutaneous lipomas_ are frequently symmetrical, and in a
certain group of cases, met with chiefly in women, pain is a prominent
symptom, hence the term _adiposis dolorosa_ (Dercum). These multiple
tumours show little or no tendency to increase in size, and the pain
which attends their development does not persist.
In the neck, axilla, and pubes a diffuse overgrowth of the subcutaneous
fat is sometimes met with, forming symmetrical tumour-like masses, known
as _diffuse lipoma_. As this is not, strictly speaking, a tumour, the
term _diffuse lipomatosis_ is to be preferred. A similar condition was
described by Jonathan Hutchinson as being met with in the domestic
animals. If causing disfigurement, the mass of fat may be removed by
operation.
[Illustration: FIG. 47.--Diffuse Lipomatosis of Neck.]
_Lipoma in other Situations._--The _periosteal lipoma_ is usually
congenital, and is most often met with in the hand; it forms a
projecting lobulated tumour, which, when situated in the palm, resembles
an angioma or a lymphangioma. The _subserous lipoma_ arises from the
extra-peritoneal fat in the posterior abdominal wall, in which case it
tends to grow forwards between the layers of the mesentery and to give
rise to an abdominal tumour; or it may grow from the extra-peritoneal
fat in the anterior abdominal wall and protrude from one of the hernial
openings or through an abnormal opening in the parietes, constituting a
_fatty hernia_. A _subsynovial lipoma_ grows from the fat surrounding
the synovial membrane of a joint, and projects into its interior, giving
rise to the symptoms of loose body. Lipomas are also met with growing
from the adipose connective tissue _between or in the substance of
muscles_, and, when situated beneath the deep fascia, such as the fascia
lata of the thigh, the characteristic signs are obscured and a
differential diagnosis is difficult. It may be differentiated from a
cold abscess by puncture with an exploring needle.
[Illustration: FIG. 48.--Zanthoma of Hands in a girl æt. 14, showing
multiple subcutaneous tumours (cf. Fig. 49).
(Sir H. J. Stiles' case.)]
#Zanthoma# is a rare but interesting form of tumour, composed of a
fibrous and fatty tissue, containing a granular orange-yellow pigment,
resembling that of the corpus luteum. It originates in the corium and
presents two clinical varieties. In the first of these, it occurs in the
form of raised yellow patches, usually in the skin of the eyelids of
persons after middle life, and in many instances is associated with
chronic jaundice; the patches are often symmetrical, and as they
increase in size they tend to fuse with another.
The second form occurs in children and adolescents; it may affect
several generations of the same family, and is often multiple, there
being a combination of thickened yellow patches of skin and projecting
tumours, some of which may attain a considerable size (Figs. 48 and 49).
On section, the tumour tissue presents a brilliant orange or saffron
colour.
There is no indication for removing the tumours unless for the deformity
which they cause; exposure to the X-rays is to be preferred to
operation.
[Illustration: FIG. 49.--Zanthoma showing Subcutaneous Tumours on
Buttocks. From same patient as Fig. 48.]
#Chondroma.#--A chondroma is mainly composed of cartilage. Processes of
vascular connective tissue pass in between the nodules of cartilage
composing the tumour from the fibrous capsule which surrounds it. On
section it is of a greyish-blue colour and semi-translucent. The tumour
is firm and elastic in consistence, but certain portions may be densely
hard from calcification or ossification, while other portions may be
soft and fluctuating as a result of myxomatous degeneration and
liquefaction. These tumours grow slowly and painlessly, and may surround
nerves and arteries without injuring them. They may cause a deep hollow
in the bone from which they originate. All intermediate forms between
the innocent chondroma and the malignant chondro-sarcoma are met with.
Chondroma may occur in a multiple form, especially in relation to the
phalanges and metacarpal bones. When growing in the interior of a bone
it causes a spindle-shaped enlargement of the shaft, which in the case
of a phalanx or metacarpal bone may resemble the dactylitis resulting
from tubercle or syphilis. A chondroma appears as a clear area in a
skiagram.
A _skiagram_ of a bone in which there is a chondroma shows a clear
rounded area in the position of the tumour, which must be differentiated
from similar clear areas due to other kinds of tumour, especially the
myeloma; when it has undergone calcification or ossification, it gives a
shadow as dark as bone.
[Illustration: FIG. 50.--Chondroma growing from infraspinous fossa of
Scapula.]
[Illustration: FIG. 51.--Chondroma of Metacarpal Bone of Thumb.]
_Treatment._--In view of the unstable quality of the chondroma,
especially of its liability to become malignant, it should be removed as
soon as it is recognised. In those projecting from the surface of a
bone, both the tumour and its capsule should be removed. If in the
interior, a sufficient amount of the cortex should be removed to allow
of the tumour being scraped out, and care must be taken that no nodules
of cartilage are left behind. In multiple chondromas of the hand, when
the fingers are crippled and useless, exposure to the X-rays should be
given a trial, and in extreme cases the question of amputation may have
to be considered. When a cartilaginous tumour takes on active growth, it
must be treated as malignant.
The chondromas that are met with at the ends of the long bones in
children and young adults form a group by themselves. They are usually
related to the epiphysial cartilage, and it was suggested by Virchow
that they take origin from islands of cartilage which have not been used
up in the process of ossification. They are believed to occur more
frequently in those who have suffered from rickets. They have no
malignant tendencies and tend to undergo ossification concurrently with
the epiphysial cartilage from which they take origin, and constitute
what are known as _cartilaginous exostoses_. These are sometimes met
with in a multiple form, and may occur in several generations of the
same family. They are considered in greater detail in the chapter
dealing with tumours of bone.
Minute nodules of cartilage sometimes form in the synovial membrane of
joints and lining of tendon sheaths and bursæ: they tend to become
detached from the membrane and constitute loose bodies; they also
undergo a variable amount of calcification and ossification, so as to be
visible in skiagrams. They are further considered with loose bodies in
joints.
Cartilaginous tumours in the parotid, submaxillary gland, and testicle
belong to a class of "mixed tumours" that will be referred to later.
#Osteoma.#--The true osteoma is composed of bony tissue, and originates
from the skeleton. Two varieties are recognised--the spongy or
cancellous, and the ivory or compact. The _spongy_ or _cancellous
osteoma_ is really an ossified chondroma, and is met with at the ends of
the long bones (Fig. 52). From the fact that it projects from the
surface of the bone it is often spoken of as an _exostosis_. It grows
slowly, and rarely causes any discomfort unless it presses upon a
nerve-trunk or upon a bursa which has developed over it. The Röntgen
rays show a dark shadow corresponding to the ossified portion of the
tumour, and continuous with that of the bone from which it is growing
(Fig. 138). Operative interference is only indicated when the tumour is
giving rise to inconvenience. It is then removed, its base or neck being
divided by means of the chisel. The multiple variety of osteoma is
considered with the diseases of bone.
The bony outgrowth from the terminal phalanx of the great toe--known as
the _subungual exostosis_--is described and figured on p. 404. Bony
projections or "spurs" sometimes occur on the under surface of the
calcaneus, and, projecting downwards and forwards from the greater
process, cause pain on putting the heel to the ground.
[Illustration: FIG. 52.--Cancellous Osteoma of lower end of Femur.]
The _ivory_ or _compact osteoma_ is composed of dense bone, and usually
grows from the skull. It is generally sessile and solitary, and may grow
into the interior of the skull, into the frontal sinus, into the cavity
of the orbit or nose, or may fill up the external auditory meatus,
causing most unsightly deformity and interference with sight, breathing,
and hearing.
Bony formations occur in _muscles and tendons_, especially at their
points of attachment to the skeleton, and are known as false exostoses;
they are described with the diseases of muscles.
#Odontoma.#--An odontoma is composed of dental tissues in varying
proportions and different degrees of development, arising from
tooth-germs or from teeth still in process of growth (Bland Sutton).
Odontomas resemble teeth in so far that during their development they
remain hidden below the mucous membrane and give no evidence of their
existence. There then succeeds, usually between the twentieth and
twenty-fifth years, an eruptive stage, which is often attended with
suppuration, and this may be the means of drawing attention to the
tumour. Following Bland Sutton, several varieties of odontoma may be
distinguished according to the part of the tooth-germ concerned in their
formation.
The _epithelial odontoma_ is derived from persistent portions of the
epithelium of the enamel organ, and constitutes a multilocular cystic
tumour which is chiefly met with in the mandible. The cystic spaces of
the tumour contain a brownish glairy fluid. These tumours have been
described by Eve under the name of multilocular cystic epithelial
tumours of the jaw.
The _follicular odontoma_, also known as a _dentigerous cyst_, is
derived from the distension of a tooth follicle. It constitutes a cyst
containing a viscid fluid, and an imperfectly formed tooth is often
found embedded in its wall. The cyst usually forms in relation to one of
the permanent molars, and may attain considerable dimensions.
The _fibrous odontoma_ is the result of an overgrowth of fibrous tissue
surrounding the tooth sac, which encapsulates the tooth and prevents its
eruption. The thickened tooth sac is usually mistaken for a fibrous
tumour, until, after removal, the tooth is recognised in its interior.
_Composite Odontoma._--This is a convenient term to apply to certain
hard dental tumours which are met with in the jaws, and consist of
enamel, dentine, and cement. The tumour is to be regarded as being
derived from an abnormal growth of all the elements of a tooth germ, or
of two or more tooth germs, indiscriminately fused with one another. It
may appear in childhood, and form a smooth unyielding tumour, often of
considerable size, replacing the corresponding permanent tooth. It may
cause a purulent discharge, and in some cases it has been extruded after
sloughing of the overlying soft parts. Many examples of this variety of
odontoma, growing in the nasal cavity or in the maxillary sinus, have
been erroneously regarded as osteomas even after removal.
On section, the tumour is usually laminated, and is seen to consist
mainly of dentine with a partial covering of enamel and cement.
_Diagnosis._--Odontomas are often only diagnosed after removal. When
attended with suppuration, the condition has been mistaken for disease
of the jaw. Fibrous odontomas have been mistaken for sarcoma, and
portions of the maxilla removed unnecessarily. Any circumscribed tumour
of the jaw, particularly when met with in a young adult, should suggest
the possibility of an odontoma. Skiagrams often give useful information
both for diagnosis and for treatment.
_Treatment._--The solid varieties of odontoma can usually be shelled out
after dividing the overlying soft parts. In the follicular variety, it
is usually sufficient to excise a portion of the wall, scrape out the
interior, and remove any tooth that may be present. The cavity is then
packed and allowed to heal from the bottom.
#Fibroma.#--A fibroma is a tumour composed of fibrous connective tissue.
A distinction may be made between the _soft fibroma_, which is
comparatively rich in cells and blood vessels, and in which the fibres
are arranged loosely; and the _hard fibroma_, which is composed of
closely packed bundles of fibres often arranged in a concentric fashion
around the blood vessels. The cut surface of the soft fibroma presents a
pinkish-white, fleshy appearance, resembling the slowly growing forms of
sarcoma; that of a hard fibroma presents a dry, glistening appearance,
aptly compared to watered silk. The soft variety grows much more rapidly
than the hard. In certain fibromas--in those, for example, which grow
from the periosteum of the base of the skull and project into the
naso-pharynx--the blood vessels are dilated into sinuses and have no
proper sheaths; they therefore tend to remain open when divided, and to
bleed excessively. Transition forms between soft fibroma and sarcoma are
met with, so that in operating for their removal it is safer to take
away the capsule along with the tumour, and the patient should be kept
under observation in view of the risk of recurrence.
The skin--especially the skin of the buttock--is one of the favourite
seats of fibroma, and it may occur in a multiple form. It is met with
also in the subcutaneous and intermuscular cellular tissue, and in the
abdominal wall, where it sometimes attains considerable dimensions.
Various forms of fibroma are met with in the mamma and are described
with diseases of that organ. The fibrous overgrowths in the skin, known
as _keloid_ and _molluscum fibrosum_, and those met with in the _sheaths
of nerves_, are described elsewhere. Fibroid tumours of the uterus are
described with myoma.
_Diffuse fibroma_ or _Fibromatosis_, analogous to lipomatosis, is met
with in the connective tissue of the skin and sheaths of nerves, and
constitutes one form of neuro-fibromatosis; a similar change is also met
with in the stomach and colon.
#Myxoma.#--A myxoma is composed of tissue of a soft gelatinous,
semifluid consistence. The pure myxoma is extremely rare, and
clinically resembles the lipoma. Myxomatous tissue is, however,
frequently found in other connective-tissue tumours as a result of
degeneration, for example, in cartilaginous tumours and in sarcomas.
Myxomatous tissue is also a prominent constituent of the "innocent
parotid tumour." Mucous polypus of the nose, which is often described as
a myxoma, is merely a pendulous process of œdematous mucous membrane.
[Illustration: FIG. 53.--Myeloma of Shaft of Humerus, causing
pathological fracture. (Mr. J. W. Struthers' case.)
(The unusual site of the tumour is to be noted.)]
#Myeloma.#--A myeloma is composed of large multinuclear giant cells
surrounded by round and spindle cells. The cut surface of the tumour
presents a deep red or maroon colour. While occasionally met with in
tendon sheaths and bursæ, and is then of an orange-yellow colour, the
myeloma occurs most frequently in the cancellous tissue at the ends of
the long bones, its favourite site being the upper end of the tibia.
Although formerly classified as a sarcoma, it is the exception for it to
present malignant features, and it can usually be extirpated by local
measures without fear of recurrence. The diagnosis, X-ray appearances,
and the method of removal are considered with the diseases of bone.
Sometimes the myeloma is met with in multiple form in the skeleton, in
association with an unusual form of protein in the urine (Bence Jones).
#Myoma.#--A myoma is composed of non-striped muscle fibres. A pure myoma
is very rare, and is met with in organs possessed of non-striped muscle,
such as the stomach, intestine, urinary bladder, and prostate. In the
uterus, which is the most common situation, these tumours contain a
considerable admixture of fibrous tissue, and are known as _fibroids_ or
_fibro-myomas_. They present on section a fasciculated appearance, which
may resemble that of a section of balls of cotton (Fig. 54). They are
encapsulated and vascular, frequently attain a large size, and may be
single or multiple. While they may occasion neither inconvenience nor
suffering, they frequently give rise to profuse hæmorrhage from the
uterus, and may cause serious symptoms by pressing injuriously on the
ureters or the intestine, or by complicating pregnancy and parturition.
The #Rhabdomyoma# is an extremely rare form of tumour, met with in the
kidney, uterus, and testicle. It contains striped muscle fibres, and is
supposed to originate from a residue of muscular tissue which has become
sequestrated during development.
[Illustration: FIG. 54.--Fibro-myoma of Uterus.
(Anatomical Museum, University of Edinburgh.)]
#Glioma.#--A glioma is a tumour composed of neuroglia. It is met with
exclusively in the central nervous system, retina, and optic nerve. It
is a slowly growing, soft, ill-defined tumour, which displaces the
adjacent nerve centres and nerve tracts, and is liable to become the
seat of hæmorrhage and thus to give rise to pressure symptoms resembling
apoplexy. The glioma of the retina tends to grow into the vitreous
humour and to perforate the globe. It is usually of the nature of a
glio-sarcoma and is highly malignant.
#Endotheliomas# take origin from the endothelium of lymph vessels and
blood vessels, and serous cavities. They show great variation in type,
partly because of the number of different kinds of endothelium from
which they are derived, and partly because the new connective tissue
which is formed is liable to undergo transformation into other tissues.
They may be soft or hard, solid or cystic, diffuse or circumscribed;
they grow very slowly, and are almost always innocent, although
recurrence has been occasionally observed. Cases of multiple
endotheliomata of the skin have recently been described by Wise.
_Angioma_, _lymphangioma_, and _neuroma_ are described with the disease
of the individual tissues.
MALIGNANT CONNECTIVE-TISSUE TUMOURS--SARCOMA
The term sarcoma is applied to any connective-tissue tumour which
exhibits malignant characters. The essential structural feature is the
predominance of the cellular elements over the intercellular substance
or stroma, in which respect a sarcoma resembles the connective tissue of
the embryo. The typical sarcoma consists chiefly of immature or
embryonic connective tissue. It most frequently originates from fascia,
intermuscular connective tissue, periosteum, bone-marrow, and skin, and
forms a rounded or nodulated tumour which appears to be encapsulated,
but the capsule merely consists of the condensed surrounding tissues,
and usually contains sarcomatous elements. The consistence of the tumour
depends on the nature and amount of the stroma, and on the presence of
degenerative changes. The softer medullary forms are composed almost
exclusively of cells; while the harder forms--such as the fibro-,
chondro-, and osteo-sarcoma--are provided with an abundant stroma and
are relatively poor in cells. Degenerative changes may produce areas of
softening or liquefaction which result in the formation of cystic
cavities in the interior of the tumour. The colour depends on the amount
of blood in the tumour, and on the presence of the products of
degeneration.
The blood vessels are usually represented by mere chinks or spaces
between the cells. This peculiarity accounts for the facility with which
hæmorrhage takes place into the substance of the tumour, the persistence
of the bleeding when it is incised or ulcerates through the skin, and
the readiness with which the sarcomatous cells are carried off and
infect distant parts through the blood-stream. Sarcomas are devoid of
lymphatics, and unless originating in lymphatic structures--for example,
in the tonsil--they rarely infect the lymph glands. Minute portions of
the tumour grow into the small veins, and, becoming detached, are
transported by the blood-current to distant organs, where they are
arrested in the capillaries and give rise to secondary growths. These
are most frequently situated in the lungs, except when the primary
growth lies within the territory of the portal circulation, in which
case they occur in the liver. The secondary growths closely resemble the
parent tumour. Sarcoma may invade an adjacent vein on such a scale that
if the invading portion becomes detached it may constitute a dangerous
embolus. This may be observed in sarcoma of the kidney, the growth
taking place along the renal vein until it projects into the vena cava.
[Illustration: FIG. 55.--Recurrent Sarcoma of Sciatic Nerve in a woman
æt. 27. Recurrence twenty months after removal of primary growth.]
In its growth, a sarcoma compresses and destroys neighbouring parts,
surrounds vessels and nerves, and may lead to destruction of the skin,
either by invading it, or more commonly by causing sloughing from
pressure. Inflammatory and suppurative changes may take place as a
result of pyogenic infection following upon sloughing of the overlying
skin or upon an exploratory incision. Once the skin is broken the tumour
fungates through the opening. Sarcomas vary in malignancy, especially as
regards rapidity of growth and capacity for dissemination. Certain of
them, such as the so-called "recurrent fibroid of Paget," grow
comparatively slowly, and are only malignant in the sense that they tend
to recur locally after removal; others--especially the more cellular
ones--grow with extreme rapidity, and are early disseminated throughout
the body, resembling in these respects the most malignant forms of
cancer. They are usually solitary in the first instance, although
primary multiple growths are occasionally met with in the skin and in
the bones.
Many varieties of sarcoma are recognised, according to its structural
peculiarities. Thus, in virtue of the size and character of the cells,
we have the _small round-celled_ and the _large round-celled_ sarcoma,
the _small_ and the _large spindle-celled_, the _giant-celled_ and the
_mixed-celled_ sarcoma. The _lympho-sarcoma_ presents a structure
similar to that of lymph-follicular tissue, and the _alveolar sarcoma_
an arrangement of cells in alveoli resembling that seen in cancers. When
there is a considerable amount of intercellular fibrous tissue, the
tumour is called a _fibro-sarcoma_.
[Illustration: FIG. 56.--Fungating Sarcoma of Arm.
(Dr. J. M'Watt's case.)]
The term _lymphangio-sarcoma_ is applied when the cells of the tumour
are derived from the endothelium of lymph spaces and vessels. The
_angio-sarcomas_ are those in which blood vessels form a prominent
element in the structure of the tumour. They are sometimes derived from
innocent angiomas, and they may be so vascular as to pulsate and on
auscultation yield a blowing murmur like an aneurysm. The
_glio-sarcoma_, _myxo-sarcoma_, _chondro-sarcoma_, and _myo-sarcoma_ are
mixed forms which usually develop in pre-existing innocent tumours. The
_osteo-sarcoma_ is characterised by the formation in the tumour of bone,
the medullary spaces being occupied by sarcomatous cells in place of
marrow. The _osteoid sarcoma_ is characterised by the formation of a
tissue resembling bone but deficient in lime salts, and the _petrifying
sarcoma_ by the formation of calcified areas in the stroma. These
varieties, although met with chiefly in the bones, may occur in soft
tissues such as muscle, and in such organs as the mamma. The pigmented
varieties include the _chloroma_, which is of a light-green colour, and
the _melanotic sarcoma_, which is brown or black. The _psammoma_ is a
sarcoma containing a material resembling sand; it is chiefly met with in
the membranes of the brain. The _chordoma_ is a rare form of tumour
originating from the remains of the notochord in the region of the
spheno-occipital synchondrosis or in the sacro-coccygeal region.
_Diagnosis of Sarcoma._--A sarcoma is to be differentiated from an
inflammatory swelling such as results from tubercle, actinomycosis, or
syphilis, from an innocent tumour, and from a cancer. The points on
which the diagnosis is founded are discussed with the different tissues
and organs.
_Treatment._--The removal of the tumour by operation is the most
reliable method of treatment; in order to be successful it must be
undertaken before dissemination has taken place, and a considerable area
of healthy tissue beyond the apparent margin of the growth must be
removed, and in tumours near the surface of the body, the overlying skin
also.
In order to prevent recurrence, a tube of _radium_, to which a silk
thread is attached, is inserted into the space from which the tumour was
removed; the thread is brought out at the drain-opening, and at the end
of a week or ten days the tube of radium is removed by pulling on the
thread. Radium causes a reaction in the tissues attended with exudation
from the vessels, for the escape of which provision must be made. If
radium is not available, the affected area is repeatedly exposed to the
action of the _X-rays_ as soon as the wound has healed. The employment
of these measures has diminished to a remarkable degree the recurrence
of sarcoma after operation.
It will readily be understood that the less thoroughly or radically the
growth has been removed, the more do we depend upon radium or the X-rays
for bringing about a permanent cure, and that in advanced cases of
sarcoma and in cases in which, on account of their anatomical situation,
removal by operation is necessarily incomplete, the prospect of cure is
still more dependent on the use of radium or of the X-rays. Finally,
there are cases in which removal by operation is impossible, the
so-called _inoperable sarcoma_; a tube of radium, to which a silk thread
is attached, is inserted into the substance of the tumour, either
through an opening made by a large trocar, or, when necessary, by open
dissection. A second tube of radium is placed upon the skin over the
tumour and is secured there by a stitch or by a strip of plaster, thus
securing a cross-fire action of the radium rays, both from within and
without, as this is found to be much more efficacious in destroying or
inhibiting the cellular elements of the growth. The tubes of radium are
left _in situ_ for from eight to fourteen days, according to the power
of the radium employed, but are moved about every second day or so in
order that every part of the tumour may be efficiently radiated. If the
tumour shrinks in size after the use of radium and becomes operable, it
should be removed before time is given it to resume its growth. It will
depend upon the subsequent course of the disease, whether or not a
second, or it may be even a third, application of radium will be
required.
Where neither radium nor X-rays is available or applicable, recourse may
be had to the injection of Coley's fluid, a preparation containing the
mixed toxins of the streptococcus of erysipelas and the bacillus
prodigiosus; or of selenium.
EPITHELIAL TUMOURS
An excessive and erratic growth of epithelium is the essential and
distinguishing feature of these tumours. The innocent forms are the
papilloma and the adenoma; the malignant, the carcinoma or cancer.
#Papilloma.#--A papilloma is a tumour which projects from a cutaneous or
mucous surface, and consists of a central axis of vascular fibrous
tissue with a covering of epithelium resembling that of the surface from
which the tumour grows. In the papillomas of the skin--commonly known as
_warts_--the covering consists of epidermis; in those growing from
mucous surfaces it consists of the epithelium covering the mucous
membrane. When the surface epithelium projects as filiform processes,
the tumour is called a _villous papilloma_, the best-known example of
which is met with in the urinary bladder. Papillomatous growths are
also met with in the larynx, in the ducts of the breast, and in the
interior of certain cystic tumours of the breast and of the ovary.
Although papillomas are primarily innocent, they may become the
starting-point of cancer, especially in persons past middle life and if
the papilloma has been subjected to irritation and has ulcerated. The
clinical features and treatment of the various forms of papilloma are
considered with the individual tissues and organs.
#Adenoma.#--An adenoma is a tumour constructed on the type of, and
growing in connection with, a secreting gland. In the substance of such
glands as the mamma, parotid, thyreoid, and prostate, adenomas are met
with as encapsulated tumours. When they originate from the glands of the
skin or of a mucous membrane, they tend to project from the surface, and
form pedunculated tumours or polypi.
Adenomas may be single or multiple, and they vary greatly in size. The
tumour is seldom composed entirely of gland tissue; it usually contains
a considerable proportion of fibrous tissue, and is then called a
_fibro-adenoma_. When it contains myxomatous tissue it is called a
_myxo-adenoma_, and when the gland spaces of the tumour become distended
with accumulated secretion, a _cystic adenoma_, the best examples of
which are met with in the mamma and ovary. A characteristic feature of
the cystic variety is the tendency the tumour tissue exhibits to project
into the interior of the cysts, constituting what are known as
_intracystic growths_. They are essentially innocent, but intracystic
growths, especially in the mamma of women over fifty, should be regarded
with suspicion and therefore should be removed on radical lines.
Transition forms between adenoma and carcinoma are also met with in the
rectum and large intestine, and these should be treated on the same
lines as cancer.
CARCINOMA OR CANCER
A cancer is a malignant tumour which originates in epithelium. The
cancer cells are derived by proliferation from already existing
epithelium, and they invade the sub-epithelial connective tissue in the
form of simple or branching columns. These columns are enclosed in
spaces--termed alveoli--which are probably dilated lymph spaces, and
which communicate freely with the lymph vessels. The cells composing the
columns and filling the alveoli vary with the character of the
epithelium in which the cancer originates. The malignancy of cancer
depends on the tendency which the epithelium has of invading the tissues
in its neighbourhood, and on the capacity of the cells, when
transported elsewhere by the lymph or blood-stream, of giving rise to
secondary growths.
Cancer may arise on any surface covered by epithelium or in any of the
secreting glands of the body, but it is much more common in some
situations than in others. It is frequently met with, for example, in
the skin, in the stomach and large intestine, in the breast, the uterus,
and the external genitals; less frequently in the gall-bladder, larynx,
thyreoid, prostate, and urinary bladder.
Tissues appear to be most liable to cancer when, having attained
maturity, they enter upon the phase of decadence or involution, and this
phase is reached by different tissues at different periods. It is not so
much, therefore, the age of the person in whom it occurs, as the age of
the tissue in which it arises, that determines the maximum incidence of
cancer. Cancer of the stomach appears and attains a maximum frequency
earlier than cancer of the skin; cancer of the uterus and mamma is more
frequent towards the decline of reproductive activity than in the later
years of life; rectal cancer is not infrequently met with during the
second and third decades. There is evidence that the irritation caused
by alcohol and tobacco plays a part in the causation of cancer, in the
fact that a large proportion of those who become the subjects of cancer
of the mouth are excessive drinkers and smokers.
A cancer may appear as a papillary growth on a mucous or a skin surface,
as a nodule in the substance of an organ, or as a diffuse thickening of
a tubular organ such as the stomach or intestine. The absence of
definition in cancerous tumours explains the difficulty of completely
removing them by surgical measures, and has led to the practice of
complete extirpation of cancerous organs wherever this is possible. The
boundaries of the affected organ, moreover, are frequently transgressed
by the disease, and the epithelial infiltration implicates the
surrounding parts. In cancer of the breast, for example, the disease
often extends to the adjacent skin, fat, and muscle; in cancer of the
lip or tongue, to the mandible; in cancer of the uterus or intestine, to
the investing peritoneum.
In addition to its tendency to infiltrate adjacent tissues and organs,
cancer is also liable to give rise to _secondary growths_. These are
most often met with in the nearest lymph glands; those in the neck, for
example, becoming infected from cancer of the lip, tongue, or throat;
those in the axilla, from cancer of the breast; those along the
curvatures of the stomach, from cancer of the pylorus; and those in the
groin, from cancer of the external genitals. In lymph vessels the cancer
cells may merely accumulate so as to fill the lumen and form indurated
cords, or they may proliferate and give rise to secondary nodules along
the course of the vessels. When the lymphatic network in the skin is
diffusely infected, the appearance is either that of a multitude of
secondary nodules or of a diffuse thickening, so that the skin comes to
resemble coarse leather. On the wall of the chest this condition is
known as _cancer en cuirasse_. Although the cancer cells constantly
attack the walls of the adjacent veins and spread into their interior at
a comparatively early period, secondary growths due to dissemination by
the blood-stream rarely show themselves clinically until late in the
course of the disease. It is probable that many of the cancer cells
which are carried away in the blood or lymph stream undergo necrosis and
fail to give rise to secondary growths. Secondary growths present a
faithful reproduction of the structure of the primary tumour. Apart from
the lymph glands, the chief seats of secondary growths are the liver,
lungs, serous membranes, and bone marrow.
It is generally believed that the secondary growths in cancer that
develop at a distance from the primary tumour, those, for example, in
the medullary canal of the femur or in the diploë of the skull occurring
in advanced cases of cancer of the breast, are the result of
dissemination of cancer cells by way of the blood-stream and are to be
regarded as emboli. Sampson Handley disagrees with this view; he
believes that the dissemination is accomplished in a more subtle way,
namely, by the actual growth of cancer cells along the finer vessels of
the lymph plexuses that ramify in the deep fascia, a method of spread
which he calls _permeation_. It is maintained also that permeation
occurs as readily against the lymph stream as with it. He compares the
spread of cancer to that of an invisible annular ringworm. The growing
edge extends in a wider and wider circle, within which a healing process
may occur, so that the area of permeation is a ring, rather than a disc.
Healing occurs by a process of "peri-lymphatic fibrosis," but as the
natural process of healing may fail at isolated points, nodules of
cancer appear, which, although apparently separate from the primary
growth, have developed in continuity with it, peri-lymphatic fibrosis
having destroyed the cancer chain connecting the nodule with the primary
growth. This centrifugal spread of cancer is clearly seen in the
distribution of the subcutaneous secondary nodules so frequently met
with in the late stages of mammary cancer. The area within which the
secondary nodules occur is a circle of continually increasing diameter
with the primary growth in the centre.
In the rare cases in which the skin of the greater part of the body is
affected, the nodules rarely appear below the level of the deltoid or
the middle third of the thigh, the patient dying before the spread can
reach the distal portions of the limbs.
Handley argues against the embolic origin of the metastases in the bones
because of the rarity of these in the bones of the distal parts of the
limbs, because of the fact that secondary cancer of the femur nearly
always commences in the upper third of the shaft, which harmonises with
the intimate connection of the deep fascia with the periosteum over the
great trochanter, thus favouring invasion of the bone marrow when
permeation has spread thus far. He claims support for the permeation
theory from the fact that the humerus is rarely involved below the
insertion of the deltoid, and that spontaneous fracture of the femur is
three times more common on the side on which the breast cancer is
situated.
The tumour tissue may undergo necrosis, and when the overlying skin or
mucous membrane gives way an ulcer is formed. The margins of a
_cancerous ulcer_ (Fig. 57) are made up of tumour tissue which has not
broken down. Usually they are irregular, nodularly thickened or
indurated; sometimes they are raised and crater-like. The floor of the
ulcer is smooth and glazed, or occupied by necrosed tissue, and the
discharge is watery and blood-stained, and as a result of putrefactive
changes may become offensive. Hæmorrhage is rarely a prominent feature,
but discharge of blood may constitute a symptom of considerable
diagnostic importance in cancer of internal organs such as the rectum,
the bladder, or the uterus.
[Illustration: FIG. 57.--Carcinoma of Breast with Cancerous Ulcer.]
_The Contagiousness of Cancer._--A limited number of cases are on record
in which a cancer appears to have been transferred by contact, as from
the lower to the upper lip, from one labium majus to the other, from the
tongue to the cheek, and from one vocal cord to the other; these being
all examples of cancer involving surfaces which are constantly or
frequently in contact. The transference of cancer from one human being
to another, whether by accident, as in the case of a surgeon wounding
his finger while operating for cancer, or by the deliberate introduction
of a portion of cancerous tumour into the tissues, has never been known
to occur. It is by no means infrequent, however, that when recurrence
takes place after an operation for the removal of cancer, the recurrent
nodules make their appearance in the main scar or in the scars of
stitches in its neighbourhood. In the lower animals the grafting of
cancer only succeeds in animals of the same species; for example, a
cancer taken from a mouse will not grow in the tissues of a rat, but
only in a mouse of the same variety as that from which the graft was
taken.
While cancer cannot be regarded as either contagious or infectious, it
is important to bear in mind the possibility of infection of a wound
with cancer when operating for the disease. A cancer should not be cut
into unless this is essential for purposes of diagnosis, and the wound
made for exploration should be tightly closed by stitches before the
curative operation is proceeded with; the instruments used for the
exploration must not be used again until they have been boiled. The
greatest care should be taken that a cancer which has softened or broken
down is not opened into during the operation.
Investigations regarding the cause of cancer have been prosecuted with
great energy during recent years, but as yet without positive result. It
is recognised that there are a number of conditions which favour the
development of cancer, such as prolonged irritation, and a considerable
number of cases have been recorded in which cancer of the skin of the
hands has followed prolonged and repeated exposure to the Röntgen rays.
_The Alleged Increase of Cancer._--Regarding the alleged increase of
cancer, it may be pointed out that it is impossible to ascertain how
much of the apparent increase is due to more accurate diagnosis and
improved registration. It is probable also that some increase has taken
place in consequence of the increased average duration of life; a larger
proportion of persons now reach the age at which cancer is frequent.
_The prognosis_ largely depends on the variety of cancer and on its
situation. Certain varieties--such as the atrophic cancer of the breast
which occurs in old people, and some forms of cancer in the rectum--are
so indolent in their progress that they can scarcely be said to shorten
life; while others--such as the softer varieties of mammary cancer
occurring in young women--are among the most malignant of tumours. The
mode in which cancer causes death depends to a large extent upon its
situation. In the gullet, for example, it usually causes death by
starvation; in the larynx or thyreoid, by suffocation; in the intestine,
by obstruction of the bowels; in the uterus, prostate, and bladder, by
hæmorrhage or by implication of the ureters and kidneys. Independently
of their situation, however, cancers frequently cause death by giving
rise to a progressive impairment of health known as the _cancerous
cachexia_, a condition which is due to the continued absorption of
poisonous products from the tumour. The patient loses appetite, becomes
emaciated, pale, and feverish, and gradually loses strength until he
dies. In many cases, especially those in which ulceration has occurred,
the addition of pyogenic infection may also be concerned in the failure
of health.
_Treatment._--Removal by surgical means affords the best prospect of
cure. If carcinomatous disease is to be rooted out, its mode of spread
by means of the lymph vessels must be borne in mind, and as this occurs
at an early stage, and is not evident on examination, a wide area must
be included in the operation. The organ from which the original growth
springs should, if practicable, be altogether removed, because its lymph
vessels generally communicate freely with each other, and secondary
deposits have probably already taken place in various parts of it. In
addition, the nearest chain of lymph glands must also be removed, even
though they may not be noticeably enlarged, and in some cases--in cancer
of the breast, for example--the intervening lymph vessels should be
removed at the same time.
The treatment of cancer by other than operative methods has received a
great deal of attention within recent years, and many agents have been
put to the test, _e.g._ colloidal suspensions of selenium, but without
any positive results. Most benefit has resulted from the use of radium
and of the X-rays, and one or other should be employed as a routine
measure after every operation for cancer.
It has been demonstrated that cancer cells are more sensitive to radium
and to the Röntgen rays than the normal cells of the body, and are more
easily killed. The effect varies a good deal with the nature and seat of
the tumour. In rodent cancers of the skin, for example, both radium and
X-ray treatment are very successful, and are to be preferred to
operation because they yield a better cosmetic result. While small
epitheliomas of the skin may be cured by means of the rays, they are not
so amenable as rodent cancers.
Cancers of mucous membranes are less amenable to ray treatment because
they are less circumscribed and are difficult of access. In cancers
under the skin, the Röntgen rays are less efficient; if radium is
employed, the tube containing it should be inserted into the substance
of the tumour after the method described in connection with sarcoma--and
another tube should be placed on the overlying skin.
In the employment of X-rays and of radium in the treatment of cancer,
experience is required, not only to obtain the maximum effect of the
rays, but to avoid damage to the adjacent and overlying tissues.
Ray treatment is not to be looked upon as a rival but as a powerful
supplement to the operative treatment of cancer.
VARIETIES OF CANCER
The varieties of cancer are distinguished according to the character and
arrangement of the epithelial cells.
The _squamous epithelial cancer_ or _epithelioma_ originates from a
surface covered by squamous epithelium, such as the skin, or the mucous
membrane of the mouth, gullet, or larynx. The cancer cells retain the
characters of squamous epithelium, and, being confined within the lymph
spaces of the sub-epithelial connective tissue, become compressed and
undergo a horny change. This results in the formation of concentrically
laminated masses known as cell nests.
The clinical features are those of a slowly growing indurated tumour,
which nearly always ulcerates; there is a characteristic induration of
the edges and floor of the ulcer, and its surface is often covered with
warty or cauliflower-like outgrowths (Fig. 58). The infection of the
lymph glands is early and constant, and constitutes the most dangerous
feature of the disease; the secondary growths in the glands exhibit the
characteristic induration, and may themselves break down and lead to the
formation of ulcers.
[Illustration: FIG. 58.--Epithelioma of Lip.]
Epithelioma frequently originates in long-standing ulcers or sinuses,
and in scars, and probably results from the displacement and
sequestration of epithelial cells during the process of cicatrisation.
The _columnar epithelial cancer_ or _columnar epithelioma_ originates in
mucous membranes covered with columnar epithelium, and is chiefly met
with in the stomach and intestine. As it resembles an adenoma in
structure it is sometimes described as a _malignant adenoma_. Its
malignancy is shown by the proliferating epithelium invading the other
coats of the stomach or intestine, and by the development of secondary
growths.
_Glandular carcinoma_ originates in organs such as the breast, and in
the glands of mucous membranes and skin. The epithelial cells are not
arranged on any definite plan, but are closely packed in irregularly
shaped alveoli. If the alveoli are large and the intervening stroma is
scanty and delicate, the tumour is soft and brain-like, and is described
as a _medullary_ or _encephaloid cancer_. If the alveoli are small and
the intervening stroma is abundant and composed of dense fibrous tissue,
the tumour is hard, and is known as a _scirrhous cancer_--a form which
is most frequently met with in the breast. If the cells undergo
degeneration and absorption and the stroma contracts, the tumour becomes
still harder, and tends to shrink and to draw in the surrounding parts,
leading, in the breast, to retraction of the nipple and overlying skin,
and in the stomach and colon to narrowing of the lumen. When the cells
of the tumour undergo colloid degeneration, a _colloid cancer_ results;
if the degeneration is complete, as may occur in the breast, the
malignancy is thereby greatly diminished; if only partial, as is more
common in rectal cancer, the malignancy is not appreciably affected.
Melanin pigment is formed in relation to the cells and stroma of certain
epithelial tumours, giving rise to _melanotic cancer_, one of the most
malignant of all new growths. Cyst-like spaces may form in the tumour by
the accumulation of the secretion of the epithelial cells, or as a
result of their degeneration--_cystic carcinoma_. This is met with
chiefly in the breast and ovary, and the tumour resembles the cystic
adenoma, but it tends to infect its surroundings and gives rise to
secondary growths.
_Rodent cancer_ originates in the glands of the skin, and presents a
special tendency to break down and ulcerate on the surface (Figs. 102
and 103). It almost never infects the lymph glands.
DERMOIDS
A dermoid is a tumour containing skin or mucous membrane, occurring in a
situation where these tissues are not met under normal conditions.
The _skin dermoid_, or _derma-cyst_ as it has been called by Askanazy,
arises from a portion of epiblast, which has become sequestrated during
the process of coalescence of two cutaneous surfaces in development.
This form is therefore most frequently met with on the face and neck in
the situations which correspond to the various clefts and fissures of
the embryo. It occurs also on the trunk in situations where the lateral
halves of the body coalesce during development. Such a dermoid usually
takes the form of a globular cyst, the wall of which consists of skin,
and the contents of turbid fluid containing desquamated epithelium, fat
droplets, cholestrol crystals, and detached hairs. Delicate hairs may
also be found projecting from the epithelial lining of the cyst.
Faulty coalescence of the cutaneous covering of the back occurs most
frequently over the lower sacral vertebræ, giving rise to small
congenital recesses, known as post-anal dimples and coccygeal sinuses.
These recesses are lined with skin, which is furnished with hairs,
sebaceous and sweat glands. If the external orifice becomes occluded,
there results a dermoid cyst.
_Tubulo-dermoids_ arise from embryonic ducts and passages that are
normally obliterated at birth, for example, _lingual dermoids_ develop
in relation to the thyreo-glossal duct; _rectal and post-rectal_
dermoids to the post-anal gut; and _branchial dermoids_ in relation to
the branchial clefts. Tubulo-dermoids present the same structure as skin
dermoids, save that mucous membrane takes the place of skin in the wall
of the cyst, and the contents consist of the pent-up secretion of mucous
glands.
_Clinical Features._--Although dermoids are of congenital origin, they
are rarely evident at birth, and may not give rise to visible tumours
until puberty, when the skin and its appendages become more active, or
not till adult life. Superficial dermoids, such as those met with at the
outer angle of the orbit, form rounded, definitely limited tumours over
which the skin is freely movable. They are usually adherent to the
deeper parts, and when situated over the skull may be lodged in a
depression or actual gap in the bone. Sometimes the cyst becomes
infected and suppurates, and finally ruptures on the surface. This may
lead to a natural cure, or a persistent sinus may form. Dermoids more
deeply placed, such as those within the thorax, or those situated
between the rectum and sacrum, give rise to difficulty in diagnosis,
even with the help of the X-rays, and their nature is seldom recognised
until the escape of the contents--particularly hairs--supplies the clue.
The literature of dermoid cysts is full of accounts of puzzling tumours
met with in all sorts of situations.
The treatment is to remove the cyst. When it is impossible to remove the
whole of the lining membrane by dissection, the portion that is left
should be destroyed with the cautery.
_Ovarian Dermoids._--Dermoids are not uncommon in the ovary (Fig. 59).
They usually take the form of unilocular or multilocular cysts, the
wall of which contains skin, mucous membrane, hair follicles, sebaceous,
sweat, and mucous glands, nails, teeth, nipples, and mammary glands. The
cavity of the cyst usually contains a pultaceous mixture of shed
epithelium, fluid fat, and hair. If the cyst ruptures, the epithelial
elements are diffused over the peritoneum, and may give rise to
secondary dermoids.
[Illustration: FIG. 59.--Dermoid Cyst of Ovary showing Teeth in its
interior.]
The ovarian dermoid appears clinically as an abdominal or pelvic tumour
provided with a pedicle; if the pedicle becomes twisted, the tumour
undergoes strangulation, an event which is attended with urgent
symptoms, not unlike those of strangulated hernia.
The treatment consists in removing the tumour by laparotomy.
#Teratoma.#--A teratoma is believed to result from partial dichotomy or
cleavage of the trunk axis of the embryo, and is found exclusively in
connection with the skull and vertebral column. It may take the form of
a monstrosity such as conjoined twins or a parasitic fœtus, but more
commonly it is met with as an irregularly shaped tumour, usually growing
from the sacrum. On dissection, such a tumour is found to contain a
curious mixture of tissues--bones, skin, and portions of viscera, such
as the intestine or liver. The question of the removal of the tumour
requires to be considered in relation to the conditions present in each
individual case.
CYSTS[3]
[3] Cysts which form in relation to new-growths have been considered
with tumours.
Cysts are rounded sacs, the wall being composed of fibrous tissue lined
by epithelium or endothelium; the contents are fluid or semi-solid, and
vary in character according to the tissue in which the cyst has
originated.
_Retention and Exudation Cysts._--_Retention cysts_ develop when the
duct of a secreting gland is partly obstructed; the secretion
accumulates, and the gland and its duct become distended into a cyst.
They are met with in the mamma and in the salivary glands. Sebaceous
cysts or wens are described with diseases of the skin. _Exudation cysts_
arise from the distension of cavities which are not provided with
excretory ducts, such as those in the thyreoid.
_Implantation cysts_ are caused by the accidental transference of
portions of the epidermis into the underlying connective tissue, as may
occur in wounds by needles, awls, forks, or thorns. The implanted
epidermis proliferates and forms a small cyst. They are met with chiefly
on the palmar aspect of the fingers, and vary in size from a split pea
to a cherry. The treatment consists in removing them by dissection.
_Parasitic cysts_ are produced by the growth within the tissues of
cyst-forming parasites, the best known being the tænia echinococcus,
which gives rise to the _hydatid cyst_. The liver is by far the most
common site of hydatid cysts in the human subject.
With regard to the further life-history of hydatids, the living elements
of the cyst may die and degenerate, or the cyst may increase in size
until it ruptures. As a result of pyogenic infection the cyst may be
converted into an abscess.
The _clinical features_ of hydatids vary so much with their situation
and size, that they are best discussed with the individual organs. In
general it may be said that there is a slow formation of a globular,
elastic, fluctuating, painless swelling. Fluctuation is detected when
the cyst approaches the surface, and it is then also that percussion
may elicit the "hydatid thrill" or fremitus. This thrill is not often
obtainable, and in any case is not pathognomonic of hydatids, as it may
be elicited in ascites and in other abdominal cysts. Pressure of the
cyst upon adjacent structures, and the occurrence of suppuration, are
attended with characteristic clinical features.
The _diagnosis_ of hydatids will be considered with the individual
organs. The disease is more common in certain parts of Australia and in
Shetland and Iceland than in countries where the association of dogs in
the domestic life of the inhabitants is less intimate. Pfeiler, who has
worked at the _serum diagnosis of hydatid disease_, regards the
complement deviation method as the most reliable; he believes that a
positive reaction may almost be regarded as absolutely diagnostic of an
echinococcal lesion.
The _treatment_ is to excise the cyst completely, or to inject into it a
1 per cent. solution of formalin. In operating upon hydatids the utmost
care must be taken to avoid leakage of the contents of the cyst, as
these may readily disseminate the infection.
A _blood cyst_ or hæmatoma results from the encapsulation of
extravasated blood in the tissues, from hæmorrhage taking place into a
preformed cyst, or from the saccular pouching of a varicose vein.
A _lymph cyst_ usually results from a contusion in which the skin is
forcibly displaced from the subjacent tissues, and lymph vessels are
thereby torn across. The cyst is usually situated between the skin and
fascia, and contains clear or blood-stained serum. At first it is lax
and fluctuates readily, later it becomes larger and more tense. The
treatment consists in drawing off the contents through a hollow needle
and applying firm pressure. Apart from injury, lymph cysts are met with
as the result of the distension of lymph spaces and vessels
(_lymphangiectasis_); and in lymphangiomas, of which the best-known
example is the cystic hygroma or hydrocele of the neck.
GANGLION
This term is applied to a cyst filled with a clear colourless jelly or
colloid material, met with in the vicinity of a joint or tendon sheath.
The commonest variety--the _carpal ganglion_--popularly known as a
sprained sinew--is met with as a smooth, rounded, or oval swelling on
the dorsal aspect of the carpus, usually towards its radial side (Fig. 60).
It is situated over one of the intercarpal or other joints in this
region, and may be connected with one or other of the extensor tendons.
The skin and fascia are movable over the cyst. The cyst varies in size
from a pea to a pigeon's egg, and usually attains its maximum size
within a few months and then remains stationary. It becomes tense and
prominent when the hand is flexed towards the palm. Its appearance is
usually ascribed to some strain of the wrist--for example, in girls
learning gymnastics. It may cause no symptoms or it may interfere with
the use of the hand, especially in grasping movements and when the hand
is dorsiflexed. In girls it may give rise to pain which shoots up the
arm. Ganglia are also met with on the dorsum of the metacarpus and on
the palmar aspect of the wrist.
[Illustration: FIG. 60.--Carpal Ganglion in a woman æt. 25.]
The _tarsal ganglion_ is situated on the dorsum of the foot over one or
other of the intertarsal joints. It is usually smaller, flatter, and
more tense than that met with over the wrist, so that it is sometimes
mistaken for a bony tumour. It rarely causes symptoms, unless so
situated as to be pressed upon by the boot.
_Ganglia in the region of the knee_ are usually situated over the
interval between the femur and tibia, most often on the lateral aspect
of the joint in front of the tendon of the biceps (Fig. 61). The
swelling, which may attain the size of half a walnut, is tense and hard
when the knee is extended, and becomes softer and more prominent when it
is flexed. They are met with in young adults who follow laborious
occupations or who indulge in athletics, and they cause stiffness,
discomfort, and impairment of the use of the limb. A ganglion is
sometimes met with on the median aspect of the head of the metatarsal
bone of the great toe and may be the cause of considerable suffering; it
is indistinguishable from the thickened and enlarged bursa so commonly
present in this situation in the condition known as bunion.
[Illustration: FIG. 61.--Ganglion on lateral aspect of Knee in a young
woman.]
Ganglionic cysts are met with in other situations than those mentioned,
but they are so rare as not to require separate description.
Ganglia are to be diagnosed by their situation and physical characters;
enlarged bursæ, synovial cysts, and new-growths are the swellings most
likely to be mistaken for them. The diagnosis is sometimes only cleared
up by withdrawing the clear, jelly-like contents through a hollow
needle.
_Pathological Anatomy._--The wall of the cyst is composed of fibrous
tissue closely adherent to or fused with the surrounding tissues, so
that it cannot be shelled out. There is no endothelial lining, and the
fibrous tissue of the wall is in immediate contact with the colloid
material in the interior, which appears to be derived by a process of
degeneration from the surrounding connective tissue. In the region of
the knee the ganglion is usually multilocular, and consists of a
meshwork of fibrous tissue, the meshes of which are occupied by colloid
material.
It is often stated that a ganglion originates from a hernial protrusion
of the synovial membrane of a joint or tendon sheath. We have not been
able to demonstrate any communication between the cavity of the cyst
and that of an adjacent tendon sheath or joint. It is possible, however,
that the cyst may originate from a minute portion of synovial membrane
being protruded and strangulated so that it becomes disconnected from
that to which it originally belonged; it may then degenerate and give
rise to colloid material, which accumulates and forms a cyst. Ledderhose
and others regard ganglia as entirely new formations in the
peri-articular tissues, resulting from colloid degeneration of the
fibrous tissue of the capsular ligament, occurring at first in numerous
small areas which later coalesce. Ganglia are probably, therefore, of
the nature of degeneration cysts arising in the capsule of joints, in
tendons, and in their sheaths.
_Treatment._--A ganglion can usually be got rid of by a modification of
the old-fashioned seton. The skin and cyst wall are transfixed by a
stout needle carrying a double thread of silkworm gut; some of the
colourless jelly escapes from the punctures; the ends of the thread are
tied and cut short, and a dressing is applied. A week later the threads
are removed and the minute punctures are sealed with collodion. The
action of the threads is to convert the cyst wall into granulation
tissue, which undergoes the usual conversion into scar tissue. If the
cyst re-forms, it should be removed by open dissection under local
anæsthesia. Puncture with a tenotomy knife and scraping the interior,
and the injection of irritants, are alternative, but less satisfactory,
methods of treatment.
_Ganglia_ in the substance of _tendons_ are rare. The diagnosis rests on
the observation that the small tumour is cystic, and that it follows the
movements of the tendon. The cyst is at first multiple, but the
partitions disappear, and the spaces are thrown into one. The tendon is
so weakened that it readily ruptures. The best treatment is to resect
the affected segment of tendon.
The so-called "compound palmar ganglion" is a tuberculous disease of the
tendon sheaths, and is described with diseases of tendon sheaths.