What Is It?
A dermoid cyst is generally a benign tumor which arises from ectodermal tissue during development. Ectodermal tissue are cells that give rise to the linings of the body, most notably the skin and all its appendages (hair follicles and hair, sweat glands, teeth, etc.). While the nomenclature sometimes gets confused, a dermoid is essentially a type of teratoma which only includes epidermal and dermal components.
While these can occur in many parts of the body, we will focus on nervous system dermoids here. During development, these primitive tissues can accidentally get trapped within the developing nervous system. Although these cystic tumors are present from birth (they are congenital) they do not always present in childhood. Because they tend to be slow growing, they can take many years before they reach a size that begins to cause symptoms.
These brain tumors have a thick cyst wall and inside are the cells that resemble those of epithelial and dermal tissues of the skin. This can include several types of tissue, most notably sweat glands, skin-like cells and hair follicles that produce hair. Therefore, a dermoid cyst typically has debris inside which can include hair and teeth as well as oily, fatty, waxy material which has been secreted and/or sloughed off into the interior of the cyst. These can occur in several areas in the central nervous system including the spinal canal and the suprasellar area (above the pituitary gland).
What Types of Symptoms Are Typical?
The symptoms associated with a dermoid cyst vary depend on its size and location. As they enlarge they can compress neurological structures, leading to neurological symptoms. These symptoms are entirely dependent on the location, but can include numbness or weakness in a part of the body, hearing or visual difficulties, as well as other nervous system deficits.
How Is The Diagnosis Typically Made?
After an in depth neurological examination, typically a CT scan
or MRI scan
of the brain or spine will reveal the cystic mass. While the appearance of these tumors is fairly characteristic, it can be confused for some other types of tumors. It should be distinguished from an epidermoid cyst
, which is a similar cyst but which only contains epithelial tissue and therefore does not have fat, hair, teeth or other such tissues inside them.
As with other tumors, to make a definitive diagnosis, tumor tissue is required to be analyzed by a pathologist.
What Are Some Common Treatments?
Treatment of these tumors depends on the specifics of each case. However, generally, for symptomatic cysts, surgical removal is often required. The goal of surgery is complete removal of the cyst and its contents but this is not always possible. If the cyst wall is adherent to important structures of the nervous system, removing them may be dangerous in some cases. In these cases, small parts of the tumor may be left behind.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.