primary umbilical endometriosis: unusual clinical presentation with microscopic diagnosis

Introduction: endometriosis, commonly occurs in the pelvic organs, mostly the ovaries, with dysmenorrhea, and menorrhagia. umbilical endometriosis is rare. symptoms include umbilical masses with swelling and pain. so it is often not recognized based on its clinical appearance. in this report, it was presented a case of primary umbilical endometriosis, accidentally found after surgery for umbilical hernia and detected in pathologic examination of tissue. patient information: a 32-year old female, was presented with umbilical bulging and mild cyclic umbilical pain, without history of abdominal surgery, or symptom of pelvic endometriosis. umbilical sonography was done in favor of fixed sac of herniation, underwent surgery, umbilical endometriosis accidentally found in pathologic examination after surgery for umbilical hernia. conclusion: although endometriosis is a common gynecological disease, primary umbilical endometriosis is a rare entity that make the diagnosis is difficult. nevertheless, this disease must be considered in the differential diagnosis of any suspected umbilical mass.