Endometriosis of umbilical cicatrix: case report and review of the literature.

Umbilical endometriosis has an estimated incidence of 0.5%-1% of all patients with endometrial ectopia. It is a very rare disease, but should be considered on the differential diagnosis of umbilical lesions. We report on a case of spontaneous umbilical endometriosis in a 38-year-old woman, with a dark brown nodule periodically bleeding, associated with severe abdominal pain. There was no history of endometriosis and she had not been pregnant before. Laparoscopic visualization of pelvic cavity showed bilateral ovarian endometrioma (it was removed while sparing the ovaries). Surgical treatment proved effective. Cutaneous endometriosis could be a sign of internal endometriosis. Presentations may be atypical and pose diagnostic difficulty, mimicking other acute diseases, e.g., skin neoplasm, folliculitis, etc., but it should be suspected in any female presenting with a painful or bleeding mass close to the umbilicus or abdominal surgical scar.