Adenocarcinoma arising in
urinary bladder or prostatic
urethra is uncommon. When they occur, the
tumor can be mistaken for metastatic lesions, especially from the
colon. Here we
report the fifth case of a primary urothelial-type
adenocarcinoma arising in the
prostate which showed enteric differentiation. The
patient was a 55 year-old
male whose prostatic
needle core
biopsy showed a high grade
adenocarcinoma which was initially
thought to be metastatic
colon cancer. A follow-up
colonoscopy was unremarkable. Subsequent
prostatectomy revealed a high grade
adenocarcinoma which was positive for cytokeratins 7 and 20,
carcinoembryonic antigen, CDX2, and high
molecular weight cytokeratin, and negative for
prostate specific antigen,
prostate specific
acid phosphatase and AMACR. A
diagnosis of urothelial-type
adenocarcinoma of the
prostate was rendered. We
review the
literature regarding this entity, and discuss the
differential diagnosis, emphasizing utility of
immunohistochemistry in making the
diagnosis. Finally, we speculate on the
behavior of these rare
tumors.