Prostatic adenocarcinoma with oncocytic features.

A case of prostatic adenocarcinoma displaying prominent oncocytic features in a 72-year-old man is presented. Histological examination both of prostatic biopsy and surgical specimen showed neoplastic cells with large eosinophilic cytoplasms that strongly immunostained with anti-mitochondrial antibody; electron microscopy analysis was also performed, documenting an increased mitochondrial count in tumour cells. Although not recognized as a distinct histologic subtype by the World Health Organization (WHO) classification, the occurrence of oncocytic features in prostatic adenocarcinoma has been sporadically noticed and was sometimes associated with a less favourable outcome. In contrast, staging procedures in our patient were negative, in spite of a high Gleason’s score, and he is alive and well at 24 months after surgery. So far, biological studies performed on oncocytic tumours from other body sites have failed to demonstrate a pathogenetic role for mitochondrial accumulation in tumorigenesis.