Primary Adenosquamous Carcinoma of the Prostate: A Rare Aggressive Tumor

Abstract

Primary adenosquamous cell carcinoma (ASC) of the prostate is a very rare and aggressive form of pros- tate cancer, making up < 1% of all diagnoses. Since its initial description by Thompson in 1942, there have been fewer than 30 cases reported in the literature. Recent reports of age-adjusted incidence rates of ASC have been shown to be about 0.03 cases per million per year making it less prevalent than pure squamous cell carcinoma, an exceedingly rare subtype in itself. The histogenesis of this tumor remains uncertain. The stimulus for the development of the squamous metaplastic cells had been thought to be related to hormone therapy or radiation therapy, or both. However, we report a case of ASC arising sponta- neously in a 60-year-old man with no previous his- tory of risk of exposure. A close scrutiny shows that 4 of the 12 well-established cases lack a history of such therapy. In primary ASC of the prostate, the prostate-specific antigen PSA level is usually within normal range, so digital rectal examination and a high index of sus- picion become part and parcel of diagnosing such rare carcinomas, as was found in this case. In addition to this diagnostic dilemma, urologists also find it difficult to manage such cases owing to lack of ad efinite treatment protocol resulting from the rarity of such tumors.