Fig. 3. Granulomatous prostatitis (arrows in A-C) with extraprostatic extension (arrowheads in A-C) in a 67-year-old male (patient no. 19) treated with Bacillus Calmette–Guérin instillation 255 days earlier (prostate-specific antigen level: 4.56 ng/mL).

A. On T2WI, the lesion is heterogeneously hypointense. B. On high b-value DWI, the lesion shows increased signal intensity. C. On CE T1WI, the lesion shows heterogeneous enhancement. D. Histologic specimen reveals caseous necrosis (white dots) corresponding to areas of poor enhancement on MRI (black arrowheads, C) (hematoxylin-eosin stain; original magnification, × 1). CE = contrast-enhanced, DWI = diffusion-weighted imaging, T1WI = T1-weighted image, T2WI = T2-weighted image