Intraductal carcinoma of the prostate in the ejaculatory duct.

Intraductal carcinoma of the prostate (IDCP) involving prostatic ducts and acini is a well-known phenomenon typically seen in a background of high-grade invasive prostatic adenocarcinoma. The current case of prostatic adenocarcinoma with Gleason score of 9 (4 + 5) invades the ejaculatory ducts, left seminal vesicle, and extraprostatic tissue. The tumor involving the left ejaculatory duct spans the lumen with preservation of native duct architecture, including basal cells, similar features described in IDCP involving prostatic ducts and acini.