Inguinal endometriosis attaching to the round ligament

We report a case of endometriosis in the right inguinal region, attached to the right round ligament in a 28-year-old woman. At the age of 20, laparoscopic left ovarian cystectomy and pelvic adhesiolysis for endometriosis was carried out. She noticed a right tender groin mass 7 months previously, and the tumour size fluctuated with the menstrual cycle. A poorly circumscribed elastic hard mass, measuring 3 cm in diameter, was palpated in her right inguinal region. Magnetic resonance imaging showed a 2.5 cm x 2.5 cm mass in the right inguinal canal and a 5.4 cm x 6.8 cm mass was seen in the left ovary. The mass enlarged during menstruation. The groin mass was removed, in addition to carrying out laparoscopic ovarian cystectomy. At operation, the groin mass was found to be in continuity with the round ligament of extraperitoneal portion. Histological diagnosis of endometriosis was made in both ovarian and inguinal tumours. After surgery, the pain disappeared completely. Worth mentioning is that MRI clearly showed the change of tumour size depending on the menstrual cycle, which aided in arriving at the correct diagnosis of endometriosis in an unusual location.