Cytologic diagnosis of prostatic malakoplakia. Report of three cases.

Three cases of prostatic malakoplakia are reported. The cytologic findings in the smears obtained by transrectal fine needle aspiration biopsy are compared with the histologic findings obtained by simultaneously performed transrectal punch biopsy. The striking cytologic finding was the presence of large isolated histiocytes with abundant foamy cytoplasm. The concentrically laminated Michaelis-Gutmann bodies that are characteristic of malakoplakia were seen both within the histiocytes and, occasionally, in the extracellular background. The smears were further characterized by a granulomatous inflammatory reaction, consisting of large numbers of polymorphonuclear leukocytes, lymphocytes and plasma cells. These findings appear to be sufficient to make a diagnosis of this rare lesion in a prostatic aspirate. To our knowledge, this is the first description of the cytology of prostatic malakoplakia.