Neoplastic endocrine cells in prostatic carcinoma: a case report with immunocytochemical and electron microscopic...

A case of a 68-year-old male with prostatic carcinoma which was partially well differentiated but largely poorly differentiated is presented in this report. The poorly differentiated area of the adenocarcinoma seemed to arise from the well-differentiated portion. The former was populated with Grimelius argyrophilic cells, and occasionally contained round, eosinophilic intracytoplasmic inclusions which appeared to be composed of a secretory substance. Immunocytochemistry revealed that endocrine cells were present in the normal portion of the gland as well as in the well-differentiated adenocarcinoma, but were more numerous in the poorly differentiated portion. The latter portion was positive for chromogranin A, endocrine granule constituents, neuroendocrine markers, serotonin, Leu 7, ACTH and neuron specific enolase. In addition, cells of poorly differentiated portion were reactive with CEA, prostatic acid phosphatase and human prostate specific antigen. Ultrastructural features observed in the poorly differentiated adenocarcinoma included five kinds of round neurosecretory granules. This was a rare case of prostatic adenocarcinoma in which the evolution from well differentiated to poorly differentiated tissue containing neuroendocrine constituents could be clearly observed.