Perianal endometrioma presented as perianal abscess: report of two cases.

Perianal endometriosis is a rare clinical presentation of the extrauterine appearance of endometrium reported in <1% of the cases. The condition is accompanied by perianal cyclic pain and a palpable mass. If diagnosed by physical examination only, the condition may be easily misinterpreted as a perianal abscess and treated improperly with incision, thus resulting in "abscess recurrence." Additional diagnostic imaging such as endoanal ultrasonography and magnetic resonance imaging should be mandatory to provide an accurate diagnosis and proper treatment resulting in low recurrence rates. We present two cases of perianal endometriomas initially diagnosed and treated as perianal abscesses.