Dermoid cyst of the ovary : A bizarre tumor, usually benign, in the ovary that typically contains a diversity of tissues including hair, teeth, bone, thyroid, etc.

A dermoid cyst develops from a totipotential germ cell (a primary oocyte) that is retained within the egg sac (ovary). Being totipotential, that cell can give rise to all orders of cells necessary to form mature tissues and often recognizable structures such as hair, bone and sebaceous (oily) material, neural tissue and teeth.

Dermoid cysts may occur at any age but the prime age of detection is in the childbearing years. The average age is 30. Up to 15% of women with ovarian teratomas have them in both ovaries. Dermoid cysts can range in size from a centimeter (less than a half inch) up to 45 cm (about 17 inches) in diameter.

These cysts can cause the ovary to twist (torsion) and imperil its blood supply. The larger the dermoid cyst, the greater the risk of rupture with spillage of the greasy contents which can create problems with adhesions, pain etc. Although the large majority (about 98%) of these tumors are benign, the remaining fraction (about 2%) becomes cancerous (malignant).

Removal of the dermoid cyst is usually the treatment of choice. This can be done by laparotomy (open surgery) or laparoscopy (with a scope). Torsion (twisting) of the ovary by the cyst is an emergency and calls for urgent surgery.

The following imaging findings may be indicative of  Benign cystic teratoma( demoid cyst) :

CT is the best modality for differentiating the various components of a teratoma.