Fine needle aspiration cytology of granulomatous prostatitis.

The fine needle aspiration (FNA) cytologic findings are presented for 18 cases of granulomatous prostatitis (12 nonspecific, 5 tuberculous and 1 eosinophilic cases). These cases represented 19% of all prostatitis cases and 2% of all prostatic aspirates examined from January 1986 to December 1987. The cytomorphologic differences between the three types of granulomatous prostatitis are described, with emphasis on the differentiation between the nonspecific and specific varieties. The differential diagnostic features between reactive changes and well-differentiated adenocarcinomas of the prostate are also presented. The findings in these cases indicate that FNA cytology is a reliable procedure for the morphologic diagnosis of granulomatous prostatitis, which can clinically mimic prostatic carcinoma when it presents as a diffuse or nodular enlargement with increased consistency.