Metastatic prostatic carcinoma histologically mimicking malignant melanoma.

Prostatic carcinoma rarely metastasizes to the skin. We describe a case in which inguinal metastasis occurred. Histologically, the tumor was composed of pale-staining cells which had pronounced epidermotropism, producing a pagetoid pattern mimicking that seen in malignant melanoma. The diagnosis was confirmed by demonstrating prostatic specific antigen in tumor cells.