MORPHOLOGIC AND NEUROENDOCRINE FEATURES OF ADENOCARCINOMA ARISING IN THE TRANSITION ZONE AND IN THE PERIPHERAL ZONE OF THE PROSTATE

: We examined retrospectively 107 step-sectioned radical prostatectomy specimens. The index tumor in each specimen was designated a transition zone carcinoma (TZCa) or a peripheral zone carcinoma (PZCa) based on its location. All tumor sections were immunohistochemically stained with chromogranin A (ChrA). A semiquantitative ChrA score (0 to 3) was assessed. ChrA-positive neuroendocrine cells were found in 83% of the index tumors. The ChrA score was significantly related to the Gleason score, the volume of the tumor, and the pathologic stage. Twenty-two percent of the index tumors were designated TZCas; 75% of these demonstrated neuroendocrine differentiation versus 85% of the PZCas. A high ChrA score of > or = 2 was found in 46% of PZCas and in only 33% of TZCas. Capsular transgression, seminal vesicle involvement, positive surgical margins, and lymph node metastasis were seen in the TZCa group in 33%, 17%, 29%, and 4%, respectively versus 58%, 20%, 48%, and 6% in the PZCa group. These findings were associated with a higher mean tumor volume in the TZCa group compared with the PZCa group. The average Gleason score of 4.5 in the TZCa group was significantly (P < 0.0001) lower than the Gleason score 6.2 in the PZCa group. Multicentricity was found in 62% of TZCas and in 49% of PZCas. Eighty-seven percent of the second tumors in the prostates with a primary TZCa were located in the peripheral zone. We conclude that the frequently occurring neuroendocrine cells population enlarges with tumor progression, especially in PZCas.(ABSTRACT TRUNCATED AT 250 WORDS)