Primary prostatic central zone adenocarcinoma

Abstract

The central zone (CZ) of the prostate is embryologically, anatomically, and histologically distinct. High-grade prostatic intraepithelial neoplasia (HGPIN) and prostatic adenocarcinoma (PAC) are encountered in the CZ, but have not been well studied. Non-CZ PAC that spread into the CZ can mimic CZ PAC. We reviewed 300 consecutive radical prostatectomies performed for PAC to identify cases showing PAC and HGPIN in the CZ. There were nine PAC (3%) localized predominantly in the CZ, presenting as a single tumor nodule (8/9) and associated with 4.5±1.1 foci HGPIN in the CZ and with only 1.7±0.5 foci in the PZ. Of the 291 non-CZ PAC, 24 cases showed satellite tumor nodules in the CZ, and 92 cases demonstrated secondary contiguous spread to the CZ. As compared to the non-CZ PAC, CZ PAC tended to have lower tumor volume, but had higher Gleason scores (8.10±0.6 vs. 6.30±0.7, p<0.05), as well as a higher incidence of a ductal carcinoma component (6/9), higher rates of capsular penetration, positive resection margins (4/9), and seminal vesicle spread (2/9). The CZ HGPIN associated with CZ PAC demonstrated cells with prominent nucleoli and formed either slender papillary structures or cribriform/solid patterns. The correlating positive biopsy cores were from the mid portion or from base of prostate and contained foci of HGPIN in 4/7 cases. The CZ PAC is characteristically accompanied by more foci of HGPIN in the CZ than in non-CZ and is associated with high grade and high stage. Preoperative diagnosis of CZ PAC can be suspected due to the histopathological features in the biopsy and is important to improve the free surgical resection rate.