Primary cutaneous endometriosis of the umbilicus: a case report.

Cutaneous endometriosis is a rare condition, especially in patients without a history of abdominal or pelvic surgery or known preexisting endometriosis. Most cases present with cyclic pain and bleeding at the site of an umbilical cutaneous nodule correlating with menses. We present an atypical case of primary cutaneous endometriosis of the umbilicus without a prior history of abdominal or pelvic surgery and without cyclic pain or bleeding.