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

Prostate cancer with marked neuroendocrine (NE) differentiation belong s to the hormone resistant carcinomas. We report the development of TS H-secreting small cell prostate cancer (SCPC) from high grade adenocar cinoma (Gleason score 8) with an elevated number of chromogranin A pos itive cells located in benign structures adjacent to the cancer. Conve rsion to SCPC was followed-up during 4 years. The initial adenocarcino ma exerted a stronger positivity for PAP than for PSA (respective stai ning indexes, Sls, 2.2 and 1.8, maximum staining 3.0). In the develope d SCPC,2 cell subpopulations that were derived from epithelial cells w ere found (positive stain for EMA and CEA, respectively) and from one of them originated CEA-positive liver metastases. Blood CEA and NSE le vels 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 grad es (Gleason score 7 and 9-10) that initially differ in staining for PS A 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 Estra cyt. Adenocarcinoma tissue specimens was slightly CEA-positive. The di sappearance of lower grade adenocarcinoma during treatment was accompa nied by the development of sarcomatoid areas that were 100% vimentin p ositive. In the last year of follow-up the primary tumor was composed only of vimentin positive sarcomatoid cells with a slight positivity f or 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 t he normal range. Scintigraphy revealed extensive liver metastases. The recorded data indicate (i) edxtremely poor prognoses associated with high grade adenocarcinomas that demonstrate stronger immunohistochemic al positivity for PAP than that for PSA (ii), chromogranin A positive cells in benign structures adjacent to the cancer as a possible paracr ine promotor of SCPC from poorly differentiated adenocarcinoma, and (i ii) a high degree of heterogeneity of both SCPC and sarcomatoid prosta tic neoplasms with some evidence for definite links (EMA and CEA) to s ecretory epithelial cells.