Bacillus Calmette-Guérin therapy-associated granulomatous prostatitis mimicking prostate cancer on MRI: A case report and literature review.

Granulomatous prostatitis following bacillus Calmette-Guérin (BCG) immunotherapy is a well-known pathological entity, developing following initiation of BCG therapy as a prophylactic measure against the recurrence of non-muscle invasive bladder cancer. In addition, there are certain imaging similarities between granulomatous prostatitis and prostate cancer, including hypoechoic area on transrectal ultrasonography and low T2 signal intensity in some prostate areas on magnetic resonance imaging (MRI). This is the report of a case exhibiting a perfect imaging cross-match between granulomatous prostatitis and potential prostate cancer on repeated MRI exams, adding two supplementary aspects to the already known similarities, namely progressive restricted diffusion and increased contrast enhancement, which are specific to prostate cancer.