Primary Malignant Melanoma of the Male Urethra

Primary malignant melanoma occurring within the male urethra is very rare. Here we report a case of malignant melanoma of the urethra in a 74-year-old man. He presented with asymptomatic gross hematuria for 5 months. His glans penis and adjacent penile skin had become discolored black 10 years ago. Cystourethroscopy showed a smooth oval-shaped elevated mass in the fossa navicularis. There were no abnormal findings in the proximal urethra and urinary bladder. Computed tomography did not detect any inguinal lymph node enlargement or distant metastases. The patient underwent partial penectomy and ilioinguinal lymph node dissection. Grossly, the distal urethra revealed an ovoid pigmented nodule, that measured 1 x 0.5 cm. Microscopic findings showed a nodular malignant melanoma arising in the urethral mucosa with pagetoid spread to the epidermis of the glans penis. There were no recurrences over a period of 12 months after surgery without chemotherapy. This is the second case of a primary malignant melanoma of the male urethra in Korea.