[Malacoplakia of the prostate].

It is reported on the extremely rare manifestation of a malacoplakia in the prostate gland. In a 67-year-old male patient the clinical diagnosis was adenoma of the prostate gland. Intra-operatively, there was the suspicion to a malignant neoplasia, which allowed only of a partial removal. The histological investigation resulted in a severe granulomatous prostatitis with characteristic cell inclusions. The ultrastructural findings confirmed the diagnosis of malacoplakia. The morphological picture, the pathogenesis and the differential diagnosis are shown.