Primary vaginal malignant melanoma: A rare case report of successful treatment with nivolumab

RATIONALE: Primary vaginal malignant melanoma is a sporadic and very aggressive tumor that is treated through surgery or radiotherapy combined with chemotherapy. Since most cases are diagnosed at an advanced stage, the operation range is extensive, the quality of life is poor, and the prognosis is gloomy. PATIENT CONCERNS: A 58-year-old woman presented irregular water-like leukorrhea for 1 month after 6 years of menopause. Positron emission tomography-computed tomography revealed a 3.1 × 2.6 × 3.2 mass on the middle and lower part of the right vaginal wall. A gynecological examination revealed a 2 to 3 cm exophytic black mass in the lower-right part of the vaginal orifice. This mass was 2 cm from the urethral orifice. Furthermore, the mucosa of the anterior inferior vaginal wall had blackened and thickened, and there were some scattered black dots at the medial labia minora. DIAGNOSIS: Due to the patient's symptoms with radiographic findings, the postmenopausal woman was diagnosed with primary vaginal malignant melanoma. INTERVENTIONS: Surgery was done to remove the mass. The patient also underwent inguinal lymph node dissection, received immunotherapy, and was treated with nivolumab. OUTCOMES: After a 6-month follow-up period, the patient underwent a routine gynecological examination with negative radiological results. Moreover, no local recurrence or distant metastases were found. LESSONS: This patient showed a good response to immunotherapy. With this treatment method, the prognosis is better for advanced-stage women, especially those who cannot endure the surgery. Local lesion resection and inguinal lymph node dissection combined with immunotherapy are recommended. The case reported here may help treat similar clinical cases.