Dermoid cysts are congenital conditions, cystic formations that develop under the skin during a baby's development in the womb. Dermoid cysts are normal tissues growing within a cellular pocket called a sac. These tissues appear and grow unexpectedly in or under the skin. Dermoid cysts can occur anywhere on the body. Those close to the skin's surface appear as small lumps, while others develop deeper within the body. These slow-growing masses contain fat and skin cells. Although they may appear tumor-like, dermoid cysts are usually not dangerous. However, surgical removal may be necessary if their location causes pressure on other organs. Dermoid cysts are also known as epidermoid cysts or dermal/epidermal inclusion cysts.