Argyrophilic, 'carcinoid-like' prostatic carcinoma. An immunocytochemical study.

Four cases of argyrophilic or carcinoid-like prostatic carcinoma were studied immunocytochemically, using immunoperoxidase stains for prostatic-specific antigen, neuron-specific enolase, hydroxytryptamine (serotonin), somatostatin, and adrenocorticotropic hormone. All four showed strong positive reaction to prostatic-specific antigen and uniformly negative results with neuron-specific enolase, hydroxytryptamine, somatostatin, and adrenocorticotropic hormone. These findings lend further support to the concept that this particular prostatic tumor is truly a carcinoma that somehow manifests a carcinoid-like histomorphology, but does not possess evidence of true neuroendocrine or carcinoidal nature.