Inguinal dermoid cyst presenting as an incarcerated inguinal hernia.

A case of an inguinal dermoid cyst presenting as an incarcerated inguinal hernia in a 18-year-old boy is reported. A differential diagnosis of masses in the inguinal region is discussed and includes not only hernias but also gynecologic and vascular lesions. Dermoid cysts must be included in the differential diagnosis. Histologically, these cysts are characterized by an external lining composed of squamous epithelium with an underlying fibroconnective tissue containing hair follicles, sebaceous, eccrine, and apocrine glands. The presence of all the skin appendages in these cysts distinguishes them from epidermoid and sebaceous cysts. The lack of structures foreign to skin differentiates them from dermoids (benign cystic teratomas) in the ovarian, testicular, retroperitoneal, and sacrococcygeal region.