Pedunculated Pigmented Eccrine Poroma of the Scalp with Increased Urinary Excretion of 5‐S‐Cysteinyldopa

Abstract

We describe a 52-year-old man with a pedunculated pigmented eccrine poroma mimicking a nodular malignant melanoma in the occipital region. The tumor was once resected but soon recurred. Histologically, the tumor mass extended from the epidermis downwards into the dermis and contained melanin granules in some areas. The tumor cells were uniformly cuboidal in appearance and had round, deeply basophilic nuclei. Initially, the urinary excretion level of 5-S-cysteinyldopa (5-S-CD) was high, but, after resection of the tumor, the level of 5-S-CD returned to normal.