Dermoid cyst
A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair, pockets of sebum, blood, fat, bone, nails, teeth, eyes, cartilage, and thyroid tissue.
As dermoid cysts grow slowly and contain mature tissue, this type of cystic teratoma is nearly always benign. In those rare cases wherein the dermoid cyst is malignant, a squamous cell carcinoma usually develops in adults, while infants and children usually present with an endodermal sinus tumor.
Location
Due to its classification, a dermoid cyst can occur wherever a teratoma can occur.
Ovarian dermoid cysts
Ovaries normally grow cyst-like structures called follicles each month. Once an egg is released from its follicle during ovulation, follicles typically deflate. Sometimes fluid accumulates inside the follicle, forming a simple (containing only fluid) cyst. The majority of these functional cysts resolve spontaneously.