[A case of malacoplakia of the prostate (author's transl)].

A case of malacoplakia of the prostate gland in a 75-year-old man is reported. This special type of granulomatous prostatitis was diagnosed by histological examination of biopsyn material. There were typical Michaelis-Gutmann corpusculates within the inflammation area. The structure of these inclusion bodies was investigated by electron microscopy. Characteristic concentric ring-shaped structures were seen as well as corpusculates which are composed of irregular cristalloid material. Some Michaelis-Gutmann bodies were found to contain short cell membrane-like structures. By histochemical investigation, both the cells possessing inclusion bodies as well as the Michaelis-Gutmann corpusculates themselves gave positive acid phosphatase reactions. The case is described because of the rarity of the malacoplakia of the prostate gland and with respect to the differential diagnosis of malignant prostate gland disease.