An unusual presentation of endometriosis.

A 25-year-old nulliparous woman attended an orthopaedic clinic with a 12-month history of right hip pain and was found to have a hard tender mass in her right groin. Fine-needle aspiration yielded a diagnosis of endometrial glands. The lesion was excised completely and the final diagnosis was round ligament endometriosis. The patient was pain free 3 months postsurgery.