A dermoid cyst in the ovary is a sac-like growth that contains hair, fat, and other tissue. It might include clumps of long hair, blood, bone, teeth, nails, eyes, cartilage and thyroid tissue. As terrifying as that sounds, these cysts can appear anywhere on the body, and are classified slightly differently by several disciplines.
A dermoid cyst may be classified as a cystic teratoma, a rare tumour found in fertile-age women. A cystic teratoma is a thick, leathery capsule covering fatty tissue. A malignant melanoma may occur in a cystic teratoma.