Melanin-like pigment in the human prostate

Twenty surgical specimens of prostate [1 histologically normal, 8 with benign hyperplasia (BPH), and 11 with cancer (PCa)] were examined by histochemical staining methods for the presence of a melanin-like pigment that we first observed in organ culture. Fontana-Masson-positive pigment was observed in epithelial cells of the normal specimen, of five BPH and of eight PCa. The distribution of pigment in BPH was unpredictable and patchy. The pigment was consistently absent in neoplastic epithelia. Silver-positive stromal cells also were observed in a number of the specimens. The epithelial pigment reacted to histochemical stains in part like melanin, in part like lipofuscin. It probably represents an endogenous pigment similar to other types of noncutaneous melanins.