Small cell anaplastic carcinoma of the prostate: report of a case with positive urine cytology.

A case of small-cell anaplastic carcinoma of the prostate, occurring in an 82-year-old man with prior prostatic adenocarcinoma, is reported. The exfoliated tumor cells in the urine were seen singly or in loose aggregates with molding. They showed scant cytoplasm and slightly pleomorphic, hyperchromatic nuclei with inconspicuous nucleoli. By electron microscopy the tumor consisted of primitive epithelial cells without glandular or neuroendocrine differentiation. The tumor pursued a highly aggressive course, and the patient died of metastatic disease 4 mo after the diagnosis.