Granulomatous prostatitis as a cause of elevated PI-RADS scores on multiparametric MRI: insights from a single institution cohort.

Granulomatous prostatitis (GP) frequently mimics prostatic adenocarcinoma on multiparametric MRI (mpMRI), producing elevated PI-RADS scores and diagnostic challenges. We retrospectively analyzed 63 patients with biopsy-proven GP (without concurrent prostate cancer) and paired mpMRI (2019-2025) to correlate radiologic and histopathologic findings. Median age was 66 years (range 41-80), median PSA 6.2 ng/mL (range 0.1-26.4), and median percentage of biopsy parts involved (PPI) was 36% (range 6-100%). PI-RADS distribution: 2 (14%), 3 (22%), 4 (24%), 5 (40%). High PI-RADS scores (4-5, n = 40, 63%) correlated with higher median PPI (48% vs. 17%, p = 0.01) vs. low PI-RADS scores (2-3, n = 23, 37%), but not PSA (6.4 vs. 5.3 ng/mL, p = 0.68). Among high PI-RADS cases, 25% had prior BCG therapy. One patient with sarcoidosis presented with PI-RADS 5 and 93% PPI. GP produces a broad PI-RADS spectrum; recognizing this imaging variability is essential for accurate diagnosis and avoiding unnecessary procedures.