Inguinal endometriosis, a rare entity of which surgeons should be aware: clinical aspects and long-term follow-up of nine cases

Introduction: Inguinal endometriosis is a rare disease and often misdiagnosed for other, more common groin pathology. We present nine cases of women with inguinal endometriosis with long-term follow-up. Methods: In this retrospective case series, the Dutch PALGA system was searched for all patients diagnosed with extrapelvic endometriosis located in the groin in the OLVG hospital, Amsterdam, between 2000 and 2016. Relevant information regarding pre- and postoperative characteristics and symptoms was collected. Follow-up consisted of a telephone call from the attending surgeon. Results: None of the patients had a history of pelvic endometriosis. Typically, they presented with a right-sided swelling in the groin. Preoperative ultrasound and MRI were in most cases inconclusive. In one of two patients fna indicated endometriosis. In only three patients the surgeon considered the diagnosis endometriosis preoperatively. Surgical removal was effective with no reported complications. A coexisting hernia sac was resected in four cases, and there was a suspicion of a persistent processus vaginalis (canal of Nuck) in three, suggesting that a persistent processus vaginalis is possibly an important key to the pathogenesis. In none of the cases there was an indication for mesh implantation. One patient was later diagnosed with pelvic endometriosis. Conclusion: Follow-up by a gynecologist is advised to check for intra-abdominal disease and inform patients on fertility perspective. Surgeons should be aware of the possibility of inguinal endometriosis in fertile women with a lump in the groin.