IMMUNOHISTOCHEMICAL STAINING AND SEROTEST MARKERS DURING DEVELOPMENT OF A SARCOMATOID AND SMALL-CELL PROSTATE TUMOR

Prostate cancer with marked neuroendocrine (NE) differentiation belongs to the hormone resistant carcinomas. We report the development of TSH-secreting small cell prostate cancer (SCPC) from high grade adenocarcinoma (Gleason score 8) with an elevated number of chromogranin A positive cells located in benign structures adjacent to the cancer. Conversion to SCPC was followed-up during 4 years. The initial adenocarcinoma exerted a stronger positivity for PAP than for PSA (respective staining indexes, Sls, 2.2 and 1.8, maximum staining 3.0). In the developed SCPC,2 cell subpopulations that were derived from epithelial cells were found (positive stain for EMA and CEA, respectively) and from one of them originated CEA-positive liver metastases. Blood CEA and NSE levels were elevated in SCPC (284 ng/ml and 24.5 ng/ml). However, blood TPS level which reflects proliferation of epithelial cells was within the normal range. The development of a <<pure>> sarcomatoid prostatic tumor from adenocarcinoma with 2 areas of similar differentiation grades (Gleason score 7 and 9-10) that initially differ in staining for PSA and PAP (SIs for PSA were 1.2 and 0.02 and for PAP were 1.6 and 0.02, respectively) was followed-up during 4 years of treatment with Estracyt. Adenocarcinoma tissue specimens was slightly CEA-positive. The disappearance of lower grade adenocarcinoma during treatment was accompanied by the development of sarcomatoid areas that were 100% vimentin positive. In the last year of follow-up the primary tumor was composed only of vimentin positive sarcomatoid cells with a slight positivity for Chromogranin A, NSE and ACTH. In parallel, normal serum PSA and PAP values and elevated CEA and NSE serotests (12.6 ng/ml and 24.7 ng/ml, respectively) were found. Blood TPS level was at the upper limit of the normal range. Scintigraphy revealed extensive liver metastases. The recorded data indicate (i) edxtremely poor prognoses associated with high grade adenocarcinomas that demonstrate stronger immunohistochemical positivity for PAP than that for PSA (ii), chromogranin A positive cells in benign structures adjacent to the cancer as a possible paracrine promotor of SCPC from poorly differentiated adenocarcinoma, and (iii) a high degree of heterogeneity of both SCPC and sarcomatoid prostatic neoplasms with some evidence for definite links (EMA and CEA) to secretory epithelial cells.