TRUS biopsy showed granulomatous prostatitis and no carcinoma.

Granulomatous prostatitis is a well described known mimicker of prostate carcinoma, clinically and on MRI.  Clinically it often presents with elevated PSA and a firm nodule on DRE. On MRI, the lesion demonstrates typical features of a highly suspicious neoplastic lesion.

Currently, histopathology is the only means of establishing the diagnosis and excluding a tumor.  

Possible causes include previous intravesical BCG treatment for bladder carcinoma, TB prostatitis, previous intervention (eg TURP) and idiopathic.