Primary malignant melanoma of the uterine cervix or vagina which were successfully treated with nivolumab.

Primary malignant melanomas (MM) originating from the gynecological tract are rare. They respond poorly to immunotherapy when compared with cutaneous MM. This study reports two cases. The first is of a 54-year-old woman with a cervical amelanotic polypoid mass who was diagnosed as having stage IB1 cervical melanoma according to the International Federation of Gynecology and Obstetrics system. At 17 months post-surgery, a computed tomography examination revealed recurrence of a 68 mm pelvic tumor. The second case is of a 37-year-old woman with a 7 cm hemorrhagic mass on the vaginal wall. The patient was diagnosed as having stage IV vaginal melanoma according to the American Joint Committee on Cancer definition. Both patients received nivolumab therapy, programmed cell death receptor 1 monoclonal antibodies, and the tumors almost disappeared. These cases may add the possibility of using colposcopy with narrow-band imaging and positron-emission tomography to diagnose and evaluate primary MM.