Multiple-Organ Involvement of Malakoplakia Mimicking Malignant Neoplasms on 18F-FDG PET/CT.

Abdominal contrast-enhanced CT was performed in a 61-year-old man with difficulties of urination and defecation for 4 months, which revealed huge rectal masses involving multiple adjacent organs, suspected as malignant lesions. 18F-FDG PET/CT was subsequently performed for staging. The images showed intense FDG uptake and slightly hyperdense masses involving rectum, bladder, prostate, left ureter, and the anterior abdominal wall at the level of the pelvic cavity. Histopathological examination confirmed the masses were due to malakoplakia, which displayed as abundant von Hansemann cells aggregated and infiltrated in lesions, with distinctive cytoplasmic inclusions termed Michaelis-Gutmann bodies.