Images in a 78-year-old man with a serum prostate-specific antigen level of
10 ng/mL. (A) Axial T2-weighted MRI scan shows a
well-encapsulated nodule in the right mid peripheral zone (arrow), which
suggests an ectopic benign prostatic hyperplasia nodule. (B)
The apparent diffusion coefficient map and (C)
diffusion-weighted image with a b value of 1500
sec/mm2 show the nodule with diffusion restriction with
prominent hypointense and hyperintense signal features (arrows), and the
(D) dynamic contrast-enhanced (DCE) MRI scan shows focal
early enhancement (arrow). The T2-weighted imaging, diffusion-weighted
imaging, DCE MRI, and overall Prostate Imaging Reporting and Data System
scores of this lesion were 2, 5, positive, and 5, respectively. Transrectal
US/MRI–fusion guided biopsy revealed Gleason 4+4 prostate cancer
within this lesion.