Comparative prostate MRI before and after chronic granulomatous prostatitis following intravesical bacillus Calmette–Guérin therapy

Background: Granulomatous prostatitis (GnP) is an interesting complication of bacillus Calmette–Guérin (BCG) therapy as it mimics prostate cancer on clinical, biochemical and imaging examinations. In the era of multiparametric prostate MRI (mpMRI), differentiation of GnP from prostate cancer on imaging is essential. Case presentation: We report a case of post-BCG GnP in a patient with nonmuscle invasive bladder cancer, presenting with a prostate-specific antigen level of 21.6 ng/ml and prostate imaging reporting and data system (PI-RADS) 5 peripheral lesions. A mpMRI performed 6 months before showed a score 2 of PI-RADS. Conclusion: The comparison of mpMRI images before and after BCG administration gives urologists, oncologists and radiologists a precise idea of the mpMRI changes that occur following BCG administration to eventually prevent unnecessary biopsies in future patients.
Lay abstract Granulomatous prostatitis is a bacillus Calmette–Guérin therapy complication that often mimics prostate cancer. This article gives radiologists, urologists and oncologists a clear multiparametric prostate MRI comparison of the changes that bacillus Calmette–Guérin prostatitis causes on the prostate gland.