Closed cutaneous sacs, with hair and sebum. Causes: enclosure of
dermoid tissue in embryo: aborted ovum: virgin gestation. Symptoms.
Treatment: Castration.
These are much less common than are simple cysts. They are closed sacs,
lined by a tissue essentially representing skin, and containing
sebaceous matter and hairs, some growing from the dermoid surface, and
others detached and formed into a loose mass.
_Causes._ These cysts have been attributed to the enclosure, in the
forming embryo, of the formative elements of dermoid tissue, which may
or may not remain latent and inactive until maturity, or until the ovary
becomes physiologically active.
Another theory is that an impregnated ovum has remained imperfect,
developing only the elements of the skin, instead of the whole fœtal
body. Many cases cannot by any possibility be included under this head,
seeing that the cyst is found at much too early an age, and its bearer
has never had sexual intercourse.
Another doctrine is that the dermoid cyst is derived from the normal
plastic or formative powers of the ovary, and the product becomes
suggestive of parthenogenesis or virgin gestation. The fact that these
cysts are not confined to the production of skin and hair, but at times
form bone, teeth, nervous and other tissues as well, corroborates this
view. On the other hand we must bear in mind that dermoid cysts are much
more common in other tissues than they are in the ovaries. Thus they are
common in the subcutaneous connective tissue and between the muscles.
The _symptoms_ do not differ essentially from those of simple cysts and
_treatment_ is mainly by castration. As the escape of the contents into
the peritoneal cavity is especially provocative of infection, the
greatest care must be taken to extract the mass whole, or to use the
most thorough antiseptic precautions.