Vulvar Endometriosis

Dyspareunia and a tender right labial mass prompted a 20-year-old woman to present to the emergency department (ED). She reported regular menses, was nulliparous, and had been treated for pelvic inflammatory disease. She was not taking any medication and used condoms for contraception. She denied fever, vaginal discharge, abdominal pain, and dysuria.

The patient had presented several weeks earlier with a labial mass that had been diagnosed as a vulvar sebaceous abscess. It had been treated with incision and drainage, but the mass recurred and was unsuccessfully retreated a total of 3 times.

Subsequently, a diagnosis of a Bartholin gland abscess was made. Because the abscess persisted despite incision and drainage procedures, a Word catheter was placed. Nevertheless, the mass continued to be painful and fluctuate in size for about a month without resolution.

On examination, the patient had a large, pink fluid-filled mass of the right labia. She was referred to a gynecologist to manage what was thought to be a persistent Bartholin gland abscess.

Bartholin gland abscesses are generally erythematous, caloric, and sharply painful. This patient, however, described cyclical pain and swelling with a pressure-like sensation. Moreover, the mass was superior to the typical location of the Bartholin gland. When asked more specifically about her bleeding pattern during menses, the patient reported dysmenorrhea.

On the basis of these symptoms, a presumptive diagnosis of vulvar endometriosis was made.
Diagnosis of this rare disorder was confirmed when a local excision was performed. The gross appearance of the mass was dark yellow and cystic, with a capsule that contained blood clots. The diagnosis was supported histopathologically by pigment-laden macrophages.

An oral contraceptive, to be taken continuously, was prescribed. The patient is now doing well
with relief of her labial pain and dysmenorrhea.

Endometriosis, characterized by growth of endometrial glands and stroma outside the endometrium, responds to hormonal stimulation at abnormal locations.¹ It is common in the reproductive years, with a 10% to 20% incidence clinically and 45% incidence rate on laparoscopic examination.² Extrapelvic
disease occurs in 12% of patients; however, vulvar endometriosis is an extremely rare site of involvement.³ Endometriosis is associated with infertility and pain. Treatment options include excision, ablation, and hormone therapy.

Ectopic transplantation of endometrial tissue is the most widely accepted theory of the 3 leading theories of the pathogenesis of endometriosis.³ However, this rare case of cyclic, vulvar endometriosis supports vascular or lymphatic dissemination. This case is worth noting because of the patient’s age at presentation of symptoms and the unusual extrapelvic site. A multidisciplinary approach was key in facilitating this patient’s final diagnosis and definitive treatment.