Adenosquamous carcinoma of the prostate.

We present an unusual variant of prostatic adenocarcinoma with obvious squamous differentiation. The squamous component is represented by cells that contain vesicular or hyperchromatic nuclei and large acidophilic cytoplasm. We could demonstrate immunohistochemically the presence of prostate specific antigen (PSA) and glial fibrillary acidic protein (GFAP) in these tumour cells. Either in adenocarcinomatous or malignant squamous components, the prostatic epithelial cells showed the two markers, namely PSA, GFAP, which may reflect the multidirectional differentiation of these cells from a pluripotent origin.