Hidden in the Scar: A Rare Case of Vulvar Endometriosis Mimicking Bartholin's Cyst at an Episiotomy Site.

Abstract

Background: Vulvar endometriosis is an exceptionally rare manifestation of extrapelvic endometriosis, particularly when located at the site of a prior episiotomy. Often misdiagnosed as more common vulvar pathologies, these lesions may present with cyclical pain and swelling, mimicking Bartholin's gland cysts or infected epidermal inclusion cysts.

Case: We report the case of a 25-year-old gravida 3 para 2 woman with long-standing dysmenorrhea, dyspareunia, and a right vulvar mass that fluctuated with her menstrual cycle. Initially presumed to be a Bartholin's cyst, the lesion failed to respond to antibiotics and sitz baths. MRI revealed a complex vaginal wall cyst without classic signs of pelvic endometriosis. Examination under anesthesia and aspiration of chocolate-colored fluid raised suspicion for an endometriotic lesion. Surgical excision confirmed endometrial glands and stroma with hemosiderin-laden macrophages-consistent with vulvar endometriosis at the site of a right mediolateral episiotomy scar. Postoperative recovery was uneventful, and the patient experienced complete resolution of symptoms.

Conclusion: This case highlights the diagnostic challenge of vulvar endometriosis in women with prior perineal trauma. Clinicians should maintain a high index of suspicion for endometriosis in cyclical vulvar masses-especially when located along episiotomy scars and unresponsive to conventional treatment. Early recognition and surgical excision can be curative and significantly improve quality of life.