Vulvar endometriosis away from a previous episiotomy scar mimicking a vulvar boil: a case report

Vulvar endometriosis is an uncommon form of extra pelvic endometriosis. It is frequently associated with previous perineal trauma or episiotomy, although lesions may occasionally occur away from sites of previous trauma. The condition may mimic other common vulvar lesions and therefore requires a high index of suspicion. A 40-year-old woman, para 1, presented with a painful vulvar swelling that was initially treated as a vulvar boil. She had undergone a full-term vaginal delivery with right mediolateral episiotomy 8 years earlier. Examination revealed a small, approximately 1–2 cm haemorrhagic cystic lesion on the right labia majora, distinctly away from the episiotomy scar. The lesion was tender and mobile, with no attachment to the underlying perineal muscles or abnormality of the overlying skin. Initial treatment with antibiotics and topical antifungal therapy did not result in improvement. On subsequent presentation around the premenstrual period, the lesion had enlarged and developed bleeding, with symptoms showing a clear cyclical relationship with menstruation. Complete surgical excision was performed under sedation and local anaesthesia. Histopathological examination confirmed vulvar endometriosis. There was no recurrence during 1 year of follow-up. Vulvar endometriosis should be considered in the differential diagnosis of a painful or recurrent vulvar lesion, particularly when symptoms show a cyclical relationship with menstruation, even when the lesion is located away from a previous episiotomy or other site of perineal trauma. Complete excision with histopathological confirmation is an effective diagnostic and therapeutic approach.