Melanomas of the glans penis, prepuce, and the corpus of the penis account for less than 1% of all melanoma cases. Due to this rarity, there is currently no standard treatment approach.
We present the case of a 59-year-old patient with tumorous formations in the prepuce area. Histology was lacking at presentation. Medical history contained excision of a single formation with the character of a viral wart in the same area 1 year previously, with electrodesiccation for relapse a few months later. Due to the appearance of new bumps, the patient presented to the Onkoderma polyclinic. Dermatological examination revealed two nodular tumor formations: one with an erosive surface in the area of the prepuce and one subcutaneous lesion in the area of the right cavernous body. Differential diagnosis included Merkel carcinoma, dermatofibrosarcoma protuberans, anaplastic T/B cell lymphoma, and achromatic melanoma. Histology showed epithelioid cell infiltration and immunohistochemistry was positive for S100 protein, HMB 45, and melan A. Achromatic preputial malignant melanoma was diagnosed. The subcutaneous formation in the area of the cavernous body was defined as an in-transit metastasis. Penectomy under spinal anesthesia was planned.
The prognosis for penile melanoma patients is currently poor, probably because of delays in diagnosis. Histopathologic evaluation after excision should be standard to prevent possible severe consequences such as penectomy and partial penile amputation.