that of the same growths as found in other parts of the body, so that
a detailed description of their structures, even though founded upon
original research, could not offer many novel facts in a field which
has been so thoroughly cultivated. Such a description would probably
repeat facts which have already been presented in other parts of this
work, and which are better and more appropriately put forth in special
treatises devoted to the science of pathology. It is proper, however,
for the sake of convenience and thoroughness, to make brief mention of
the structure of brain tumors, and especially to dwell upon certain
features of these morbid growths which may be considered
characteristic of their encephalic location, and hence have not only
pathological but also clinical interest. It is hardly worth while to
refer to speculations which aim to elucidate the very foundations of
the science, except that in a few of these theories we gain an
additional insight into both the structure and conduct of some very
characteristic brain tumors.
Cohnheim's theory was that tumors are formed from foci of embryonal
tissue which had been non-utilized or left over in the intra-uterine
development of the body. Many have not accepted this idea, but have
rather considered that in tumors we witness a reversion of tissue to
lower or embryonic types.[28] Whether we accept either or neither of
these propositions, the idea sought to be conveyed is that in all
these morbid structures we have a tissue of low or degraded character,
springing in most instances from a connective or non-differentiated
tissue. This fact is brought out very clearly in many of these
intracranial growths. Virchow[29] has said that tumors originate in
the cells of the connective tissue, although his law has been
condemned as not of sufficient breadth, since it seems to ignore the
epithelial and myomatous tumors. Dermoid cysts, of which an example is
given in the table of spinal tumors,[30] are said to illustrate the
embryonic function revived—_i.e._ the tendency of lower tissues to
spontaneously differentiate into higher and more complex ones.
[Footnote 28: Article “Pathology” in _Brit. Encyc._, by C. Creighton.]
[Footnote 29: Quoted by Cornil and Ranvier.]
[Footnote 30: Page 1107.]
The gliomata are among the most common and characteristic tumors of
the cerebro-spinal axis, to which system and its prolongation into the
retina they are confined. They invariably spring from the neuroglia or
connective tissue of the nerve-centres, and reproduce this tissue in
an embryonal state. They greatly resemble the brain-substance to
naked-eye inspection, but have, histologically, several varieties of
structure. {1047} These variations depend upon the relations of the
cell-elements to the fibres or felted matrix of the neoplasm. In the
hard variety the well-packed fibrous tissue preponderates over the
cell-elements, and we have a tumor resembling not a little the
fibromata (Obernier). The second variety, or soft gliomata, show a
marked increase of cells of varied shapes and sizes, with a rich
vascular supply which allies these growths to the sarcomata. The
elements of gliomata sometimes assume a mucoid character, which allies
them, again, to the myxomata.
[Illustration: FIG. 43. Flat Glioma-cell with its Fibrillar
Connections (Osler).]
[Illustration: FIG. 44. (1) Homogeneous translucent fibre-cell; (2)
cells like unipolar ganglion-cells; (3) giant cell (Osler).]
W. Osler has recently described[31] to the Philadelphia Neurological
Society the structure of certain of these tumors, from which we
abstract the following facts: One point referred to is that gliomata
sometimes contain larger cells and coarser fibres than are usually
shown. The structures are (1) The “spinnen” or spider-cells
(characteristic of glioma), which present variations in size; (2)
large spindle-shaped cells with single large nuclei (some of the
largest cells met with in tumors); (3) cells like the ganglion-cells
of nerve-centres, with large nuclei and one or more processes: some
are balloon-shaped with single processes; they are larger than the
spider-cells; (4) translucent band-like fibres, tapering at each end,
without nucleus or granular protoplasm, regarded as a vitreous or
hyaline transformation of the large spindle-cells. Klebs (quoted by
Osler) holds that the ganglion-like cells are derived from the
nerve-cells of the gray matter, “and that in the development of this
variety all elements of the nerve-tissue participate.” Osler examined
the advancing region of {1048} the tumor, and was not able to satisfy
himself that the nerve-cells were in process of proliferation. He
thinks they are connective-tissue elements. He has seen but two out of
five cerebral gliomata which were of small-celled type.
[Footnote 31: “Structure of Certain Gliomas,” _Philada. Med. News_,
Feb. 20, 1886.]
The gliomata are subject to fatty degeneration, which usually occurs
in the central (older) portions of the mass. The more vascular forms
are also peculiarly liable to hemorrhage, which is probably caused in
some instances by this process of retrograde metamorphosis. These
hemorrhages resemble apoplexies, not only in their clinical features,
but also on gross examination. Great care is therefore often necessary
at the autopsy to distinguish such a hemorrhage, occurring as it does
in a brain-like neoplasm, from one caused by the rupture of a diseased
artery. The hypertrophy of the pineal gland, sometimes noted, is
caused by the formation of gliomatous tissue. Under the microscope it
is necessary carefully to distinguish some forms of inflammatory new
formations from the gliomata. We have recently seen, by the courtesy
of E. N. Brush of the Pennsylvania Hospital for the Insane,
photographs of microscopic sections from the ependyma of the lateral
ventricles in a case of general paresis, which showed the structure of
this degenerated tissue to be a compound of fibres and cells of marked
resemblance to gliomatous tissue.[32]
[Footnote 32: These micro-photographs were prepared in the laboratory
of the State Lunatic Asylum, Utica, New York, by Theodore Deecke.]
Sarcomata of the brain are common, as our table shows. In them the
cell-elements predominate, both in the large- and small-celled
variety. They are malignant and grow rapidly. The form known as
alveolar sarcoma, which has a distinct stroma, is to be distinguished
from the cancers; which has probably not always been done.
Tubercle, according to Ross, is the most common of all forms of brain
tumor. Our table shows 13 cases out of 100, the gliomata and sarcomata
being in larger number. Its favorite seat is in the cortex of both the
cerebrum and cerebellum: some observations appear to show that it is
more common in the cerebellum and mid-brain region than in the
fore-brain, and in children than in adults; some of which points
distinguish it from the gummata, which are more common in adults and
occur anywhere. Tubercle is another form of development from the
connective tissues, usually dependent upon a constitutional taint or
predisposition: in it the cell-elements have generally undergone a
degeneration into an amorphous cheesy mass. It is apt to be multiple
and accompanied by a similar deposit in other organs of the body.
True neuromata are probably very rare growths, and it is likely that
some tumors which have been described as such are really
connective-tissue tumors of a gliomatous nature, in which some of the
cell-elements have been mistaken for the ganglion-cells. Obernier[33]
says that these tumors are small and grow from the gray matter on the
surface, also on the ventricular surfaces. They are also found in the
white matter. He says they are only found in persons having some
congenital or acquired aberration; by which is probably meant some
other well-marked neurosis or psychosis. The one hundred tabulated
cases afforded no examples of neuromata.
[Footnote 33: _Op. cit._]
Myxomata are not, histologically, to be distinguished from the {1049}
gliomatous tissues by anything but the peculiar mucoid changes which
their structures have undergone. They are more rare in the brain, as
our tables show, than in the spinal cord.
Lipomata are very rare in the brain, according to most observers. The
table shows but one example. These tumors, as their name signifies,
are made of fat-bearing tissues—another of the connective-tissue
class.
The angiomata, somewhat rarely found within the skull, are noted for
their abnormal development of the vascular tissues: they are composed
mainly of blood-vessels and the connective tissue, which supports them
in closely-packed masses. They also present cavernous enlargements.
They are of especial interest in cerebral pathology, because the
lesion known as pachymeningitis hæmorrhagica, often found in dementia
paralytica, is considered by some to be angiomatous; although by far
the most generally accepted view of this latter condition is that it
is due to arterial degeneration, and in part is an inflammatory
exudate.
Syphilitic tumors, or gummata, are, like tubercle, a special
development with degeneration from the connective tissue, due to a
constitutional taint. This new growth is sometimes single, sometimes
multiple. The corpuscles of the neuroglia are the apparent points of
origin of the tumor, the substance of which is the firm, peculiarly
gummy, and non-juicy material from which the name is derived. It would
be impossible in our allowed space to trace this neoplasm through the
successive stages of its development. It has especial clinical
interest, inasmuch as it and its damage are probably amenable to
specific treatment when it has not progressed to too great a
destruction of brain-tissue.
The true cancers, or epithelial neoplasms, are not a common form of
tumor of either the brain or spinal cord. They present, as in other
parts of the body, a stroma forming alveolar spaces in which are
contained the nests of epithelial cells. These tumors thus present
characteristic differences in their histology from the
connective-tissue or mesoblastic groups, but clinically no very
special interest attaches to them. Their location, the rapidity of
their growth, and their fatal import are points which they share with
most other new growths of the cranial cavity.
The cholesteotomata, or pearl cancers, consist of hardened epithelial
cells which have undergone a sort of fatty degeneration.
The psammomata are loosely described as tumors containing sand-like
bodies, which bodies are normal about the pineal gland. These
sand-like bodies are found in tumors of some histological diversity,
and do not appear to have much identity of their own. They occur in
sarcomata and carcinomata, and are probably not to be distinguished
from mere calcareous infiltration and degeneration. They are most
common in sarcomata, as this is one of the most common of cerebral
tumors.
True osteomata—_i.e._ tumors with the structure of true bone—are
probably rare in the brain, although more common on the inner table of
the cranium; but the deposition of calcareous salts has been recorded
in a variety of conditions. F. X. Dercum, in a recent paper read
before the Philadelphia Pathological Society,[34] has recorded the
autopsy of a paretic dement in which case calcareous deposits were
scattered throughout both hemispheres and the cerebellum. He believes
that “the areas in {1050} which the concretions were found were
probably foci of encephalitis of greater intensity than elsewhere. In
these foci inflammatory changes in the walls of the vessels became
pronounced; besides which the vessels increased enormously in size and
number; so marked is this increase that these foci could, with perfect
propriety, be called angiomata.” This is followed by proliferation of
the neuroglia, compression and destruction of nerve-tissue, and
deposit of the calcareous salts especially about and upon the coats of
the vessels. This case illustrates in the simplest manner the
formation of both vascular and sand tumors.
[Footnote 34: _The Medical News_, April 24, 1886, p. 460.]
Pacchionian bodies are very common in the brain, and are really small
fibromata. They may form true tumors (Cornil and Ranvier) capable of
wearing away the bones of the cranium. In fact, even when small they
may have corresponding indentations in the skull. They are not to be
mistaken for tubercle. Clouston[35] has described excrescences from
the white matter of the brain, growing through the convolutions,
projecting through the dura mater, and indenting the inner table of
the skull; which new growths he calls hernia of the brain through the
dura. We have not seen such a condition described elsewhere, and think
that we have here probably Pacchionian bodies growing from the pia
mater. They were found in a case of tumor of the cerebellum.
[Footnote 35: _Journ. Ment. Sci._, xviii. p. 153.]
A cystic formation, constituting a veritable tumor, not unfrequently
occurs in the pituitary body and mounts into the third and lateral
ventricles. Echinococci and hydatids also occur, and have the same
natural history as these parasitic offspring have when found in other
parts of the human body.
Obernier refers to an enchondrosis of the basilar process. Our table
presents one case of enchondroma.
Some of the gross appearances found on autopsies of tumors of the
brain are worthy of note. Often an area of congestion or inflammation,
especially of the membranes, is seen about the new growth, and the
brain-substance in its immediate vicinity is much more frequently
softened. The cerebro-spinal fluid is increased, and, especially when
direct pressure has been exerted upon the veins of Galen, are found
distended lateral ventricles. When a tumor does not approach the
surface, but has attained some size, the hemisphere in which it is
located often has a bulging appearance, crowding over upon its
neighbor, and the convolutions are flattened by the pressure. The
cranial nerve-trunks are occasionally involved in or stretched by the
tumor, and also occasionally the bones of the vault or base of the
cranium are extensively eroded. This happens especially in cancer and
osteo-sarcoma.
A few remarks should be made about the methods of making post-mortem
examinations and the gross appearances and conditions likely to be
found in brain-tumor cases. As not a few intracranial tumors are
connected with the bone or with the dura mater, the latter being
adherent to the skull-cap in some positions because of inflammation
arising from the seat of the growth, especial care should be taken in
removing the calvarium. Examination of the external surface of the
dura mater will sometimes reveal the presence of a growth beneath or
incorporated with this membrane. The dura mater should not be roughly
dragged from the surface of the brain, but should be carefully removed
by a {1051} process of partial dissection. During this process a
meningeal growth will sometimes be found growing apparently from the
fused membrane. In such cases it is usually better to so proceed as
not to entirely separate the outer membrane from the growth. Indeed,
this cannot be done sometimes without injury directly to the specimen,
and especially to its cerebral surroundings. The dura mater having
been removed, a marked opacity, sometimes a dirty-brown hue shading
off into a lighter color, will indicate to the eye the probable
presence of a tumor beneath and growing from the pia mater of the
cortex. In such a case, and even when no such appearance is present,
but a tumor is suspected, the fingers passed carefully over the
cerebral surface will feel a hard, and it may be nodulated, mass at
some position. A growth, having been located in this way, should not
be roughly handled or at once examined by section. An effort should be
made to accurately localize it, not only with reference to lobes, but
also with reference to convolutions and fissures, and even special
portions of these. This is best done, after a thorough examination has
been made of the pia mater, by carefully stripping the pia mater from
the brain, beginning at points some distance from the growth and
gradually approaching it, and leaving the pia mater for a short
distance around the growth connected with it. The location having been
fixed and other portions of the brain having been examined, if it is
not possible or desirable to retain the entire brain as a specimen, a
block should be removed embracing a considerable portion of healthy
brain-tissue on all sides of the tumor. In order to study the gross
internal appearance of the tumor, it is a good plan to make a clean
section through the middle of the tumor. From each side of this cut
fragments can be taken for microscopical examination without deranging
appreciably the size and appearance of the tumor.
When the tumor is not meningeal or cortical, or not situated at the
base or floor of the skull, its presence may be revealed, when it is
in centrum ovale and of considerable size, by either hardness or
fluctuation of the hemisphere in which it is located, this fluctuation
not being due to the tumor itself so much as to the breakdown of
tissue around it. Large sections in known positions with reference to
convolutions and ganglia should be made when examined for tumors
deeply situated. If possible, sections close to and just before and
behind the growth should be made, so as to assist in the accurate
localization.
Small tumors are not infrequently overlooked by careless observers,
and even growths of considerable size have escaped discovery by one
examiner to be found by another. Tumors in certain special localities,
as between the temporo-occipital lobe and the superior surface of the
cerebellum in the great longitudinal fissure, or small growths in the
substance of the cerebellum or deep in the Sylvian fissure, are more
likely than others to be passed by, although this, of course, is not
likely to occur when the examination is made by a competent or careful
physician.
DIAGNOSIS.—The diagnosis of the existence of an intracranial tumor, as
a rule, is not difficult. It can be made with greater certainty than
that of almost any other serious encephalic disease.
It is sometimes important to decide as to the nature of an
intracranial neoplasm, particularly whether or not it is syphilitic.
Little is to be gained by following the plan adopted by some
physicians, of treating all cases as if they were due to syphilis, on
the principle that these {1052} are the only forms of tumor which can
be reached by treatment. The pitiable condition of such patients is
sometimes thus made worse. In every case careful and persistent
efforts should be made to obtain an authentic previous history from
the patient. Whenever possible the physician should search directly
for the physical evidences of the former existence of syphilis—for
cicatrices on the genitals and elsewhere, for nodes and depressions,
for post-cervical and other swellings, etc. A history of previous
disease of the throat and of pains in bones and nerves, of
epileptiform attacks, of headache, and eye symptoms which have
disappeared under treatment, should be sought out. It is not well to
give too much credence to the stories of patients, who are not always
willing to admit their past lapses from virtue; but, on the other
hand, the plan of suspecting everybody who presents advanced cerebral
symptoms is often a grievous wrong. Not infrequently external cranial
nodes are present in cases of intracranial syphilis.
Carcinomata and sarcomata, particularly the former, are comparatively
rapid in their progress. They sometimes involve the bones of the
skull, even to the extent of perforation.
The existence of an inherited tendency and of tuberculosis in other
organs, with the special phenomena of general tuberculosis, assists in
the diagnosis of tubercular tumors.
The frequent occurrence of gliomata in early life, and the
comparatively frequent absence of severe irritative symptoms, with the
well-preserved general nutrition of the patient, speak for these
growths.
Cerebral abscess is, on the whole, more difficult to diagnosticate
from intracranial tumor than any other affection. Abscess, however,
more frequently than tumor, can be traced directly to a traumatism. It
is often associated with disease of the internal ear. Obernier speaks
of the headache of cerebral abscess as slight, but this does not
correspond with usual experience. Headache, on the whole, may be
oftener absent or less agonizing in abscess than in tumor, but it is
frequently present, and sometimes of great severity. Its greater
mildness in a few cases is to be explained by the fact that abscess
does not produce so much pressure within the intracranial cavity, and
does not so frequently cause irritation of the branches of the
trigeminus in the dura. Undoubtedly, the symptoms of abscess often
remain for a long time comparatively latent, with then a sudden
outburst of violent symptoms. The course of brain tumor is more
uniformly and steadily progressive, and febrile phenomena, the results
of pyæmia, are of more frequent occurrence in abscess than in tumor.
In old cases of tumor it is sometimes necessary to differentiate
between it and the results of various forms of apoplexy, such as
hemorrhage, thrombosis, and embolism. Cerebral hemorrhage, embolism,
or thrombosis leaves a condition of paralysis, sometimes with, but
usually without, accompanying spasm or convulsion, which simulates
closely the paralysis and other permanent conditions of cases of tumor
occurring in the same cerebral locality. In these cases, in the first
place, the history of the disease will throw considerable light upon
the diagnosis. In both hemorrhage and embolism the history is usually
one of a sudden attack without special premonitory symptoms.
Hemorrhage gives usually a precedent history of diseased kidneys,
hypertrophied heart, or {1053} atheromatous blood-vessels, and occurs
generally in advanced life; embolism, a history of rheumatism and
valvular disease of the heart, occurring at any period of life, early
or late. In brain tumor the previous history is usually one of
traumatism, of constitutional infection, or of a special predisposing
diathesis. Blows and falls upon the head are common antecedents, or a
history of syphilis, tuberculosis, scrofula, or cancer is present.
Tumor, like embolism and unlike hemorrhage, may occur at any time of
life. While slight or dull headache, with more or less vertigo, may be
present in cases of hemorrhage and thrombosis, the severe and often
agonizing headache, with vomiting and serious vertiginous attacks,
which precedes the paralytic or other phenomena of tumor, is a much
more conclusive symptom in the latter cases than in the former. Choked
discs and optic neuritis are much more likely to occur in tumor than
in the other affections.
Brain tumor must sometimes be diagnosticated from the head symptoms of
some form of Bright's disease. A case not long since presented itself
to one of us with a history of having suffered at frequent intervals
for two years with headache of gradually increasing severity. Dimness
of vision and slight temporary œdema of the feet, circumscribed and
painful swellings along the lymphatics of the thighs and legs, with
some mental irritability, were other marked symptoms. The patient had
been attended by several physicians of prominence, one of whom had
diagnosticated tumor of the brain. The violent, apparently agonizing
headache, with the diminution of vision, and the absence of marked
symptoms indicating other organic disease, made the diagnosis of a
growth in some non-excitable region of the cerebrum most probable.
Examination of the urine showed no albumen. Careful examination of the
eye-ground with the ophthalmoscope, however, revealed the appearances
of retinitis albuminurica. Under a treatment directed to the relief of
chronic nephritis the patient's headache and other symptoms improved.
It must not be forgotten just here, however, that, on the one hand,
ophthalmoscopic appearances very similar to those of albuminuric
retinitis are sometimes present in rare cases of brain tumor, and also
in other constitutional disorders, such as leukæmia; and, on the other
hand, that, as stated by Norris,[36] exceptional forms of albuminuric
retinitis have been reported where the only change seen in the fundus
oculi was pronounced choking of the disc.
[Footnote 36: _Op. cit._]