General Medical Information

Dermoid Cyst

Sharen J. Knudsen
Byron J. Bailey

Ectodermal cysts containing epithelial lining and adnexal tissue have an origin similar to that of neurogenic tumors. Defective obliteration of the dural projection through the foramen cecum results in entrapment of epithelial elements as the dural tract resorbs. A sinus tract results from invagination of the epithelia, which can occur anywhere from nasal tip to foramen cecum. A cyst forms in a closed tract. Sessions RB prefers the term nasal dermal sinus cysts to describe these lesions because most are associated with a sinus track. Dermoid cysts usually are present at birth and have a sinus opening anywhere from columella to nasion. A tuft of hair frequently protrudes from the ostia. Simple dermoid cysts involve only the skin and nasal bones. Complex dermoid cysts can involve the undersurface of the nasal bones and extend through the cribriform plate to the dura. The patient usually has a history of meningitis or CSF leak if a dural connection exists. Surgery is the recommended treatment, but recurrence is common despite a careful surgical approach. Craniotomy is needed for dermoid cysts with known dural connections, but many complex dermoid cysts can be approached extracranially. The complications of surgery are meningitis and CSF leak.