We report a case of primary malignant melanoma (MM) of the female urethra. A 60-year-old female complained bleeding from the urethral meatus. MRI revealed a mass of 20 mm at the external urethral meatus. Pathological examination of transurethrally resected specimens revealed MM with stromal invasion. She underwent total urethrectomy plus cystostomy and sentinel lymph node biopsy. The tumor was pathologically confined in the specimen and no lymph node metastasis was found. She received interferone β as adjuvant therapy. However, she developed bilateral adrenal and pulmonary hilar lymph node metastases 1 year after urethrectomy. Although she started to receive nivolumab as salvage therapy, the disease progressed as well as development of interstitial pneumonia (IP) after four cycles. Following improvement of IP with steroid therapy, she started to receive ipilimumab, which resulted in the development of intolerable IP of grade 3. The patient finally died of MM 19 months after the initiation of treatment.
Keywords: Immune checkpoint inhibitors; Malignant melanoma of urethra.