Endometriosis of extra-pelvic round ligament, a diagnostic dilemma for physicians

A 49-year-old multiparous woman presented with a swelling in the left groin of 6 months duration. The swelling was associated with a dull aching pain. The patient reported increase in size of the swelling during lifting of heavy weights. Menstrual history was normal and there was no increase in pain over the swelling during menstruation. She underwent a caesarean section 20 years ago and the scar had healed by primary intention. She was provisionally diagnosed to have a left-sided inguinal hernia. Ultrasonography showed a multiloculated cyst measuring 5.3×1.5×5.2 cm within the inguinal canal. The patient had excision of the cyst under spinal anaesthesia. Intraoperatively the cyst was found to arise from the left round ligament. It measured 7×6 cm extending to the left lateral vaginal wall. Histopathology revealed endometriosis of the round ligament. Her gynaecological assessment was normal and they recommended no further treatment. On followup the patient was asymptomatic and wound had healed well.