Episiotomy scar endometriosis misdiagnosed as a stitch granuloma eight years after vaginal delivery: a case report

Abstract

Endometriosis of an episiotomy scar is an uncommon form of extrapelvic endometriosis in which endometrial-like tissue implants within a perineal obstetric scar and undergoes cyclical hormonal change. It is often misdiagnosed, because the classical triad of previous episiotomy, a tender perineal nodule, and cyclical pain is complete in only about half of cases, and because the swelling mimics common perineal conditions such as suture granuloma, abscess, or Bartholin cyst. We report a 32-year-old woman, para 2, with an eight-year history of a painful swelling at her left episiotomy site. The cyclical nature of the pain had been overlooked at several earlier consultations, and she had been treated empirically with antibiotics for a presumed antibioma without benefit. Pelvic ultrasound was normal, and a working diagnosis of stitch granuloma was made. At operation a firm mass of 4 by 3 cm was found over the left labia minora; on incision it released thick chocolate-brown fluid, an appearance typical of an endometriotic cyst. The lesion was excised completely with a 1 cm margin of healthy tissue, and histopathology confirmed endometriosis. Recovery was uneventful and she remained free of recurrence at 12 months. Scar endometriosis should be considered in any reproductive-age woman with a long-standing painful perineal lump at an episiotomy site, even when cyclical symptoms are not reported spontaneously. A directed menstrual history and complete surgical excision with a healthy tissue margin are the keys to diagnosis and cure.