Clonality of sarcomatous and carcinomatous elements in sarcomatoid carcinoma of the prostate.

Sarcomatoid carcinomas of the prostate are rare malignancies composed of carcinomatous and sarcomatous elements. Their etiology is uncertain and may represent a single malignant process or a mixture of two distinct malignancies. We report a clinical case of a patient who presented with locally advanced disease and was treated with hormonal and cytotoxic chemotherapy, but ultimately developed distant metastasis and died of the disease. A loss-of-heterozygosity analysis of the primary and metastatic tissues provided compelling evidence that the carcinomatous and sarcomatous elements are clonally related, supporting the hypothesis that a single malignant process underlies the etiology of sarcomatoid carcinoma of the prostate.