Penile metastasis from rectal cancer by PET/CT.

It is extremely rare for rectal tumors to metastasize to the penis, and when it occurs, it is associated with poor prognosis. The appearance of penile metastasis from rectal primary tumor on PET imaging has not been widely reported. We report a case of a 70-year-old man with previous history of treated stage III adenocarcinoma of the rectum 26 months ago. The restaging 18F-FDG PET/CT scan demonstrated a hypermetabolic mass at the base of his penile shaft. This lesion was confirmed on core biopsy to be a metastatic adenocarcinoma of colorectal origin consistent with the known primary rectal tumor.