The transrectal ultrasound and MRI appearances of granulomatous prostatitis and its differentiation from carcinoma

AIMS AND METHODS: Granulomatous prostatitis is a benign inflammatory condition of the prostate which can be mistaken for prostatic carcinoma both clinically and on ultrasound, but is distinguishable histologically. The transrectal ultrasound (TRUS) and magnetic resonance imaging (MRI) appearances of 10 patients with histologically confirmed granulomatous prostatitis were evaluated to try and identify any correlation between the two techniques or any specific features on MRI to help distinguish it from carcinoma. Clinical findings and serum prostatic specific antigen (PSA) levels were also evaluated. RESULTS: In five patients, both TRUS and MRI were concordant, showing only changes of benign prostatic hypertrophy (three patients) or showing no abnormality (two patients). In a further three patients, both TRUS and MRI were abnormal, with appearances suggestive of carcinoma. One of these patients had tuberculous prostatitis and had a past history of tuberculosis. In the remaining two patients, there was a discrepancy between TRUS and MRI findings, carcinoma being suspected on TRUS in one with a normal MRI, and carcinoma suspected on MRI in the other with a normal TRUS. CONCLUSION: There is no pattern of clinical, biochemical, ultrasound or MRI findings that allows a specific diagnosis of granulomatous prostatitis to be made, or differentiation from prostatic carcinoma.