Objectives: Intraductal carcinoma of the prostate (IDC-P) is usually associated with high grade, aggresive acinar adenocarcinomas. IDC-P is supposed to result from the spread of the adenocarcinoma along the prostatic ducts. IDC-P rarely occurs without invasive carcinoma or with a coexistent low grade adenocarcinoma.
Material and methods: We report two patients, 66 and 75 year-old, who presented IDC-P and low-grade acinar adenocarcinoma foci in their radical prostatectomy surgical specimens.
Results: Acinar adenocarcinomas were grade group 1, PTEN+, pT2. In the first case, the invasive adenocarcinoma was adjacent but nor intermingled with the IDC-P, and a discordance in the immunophenotype between them was outstanding (positivity for ERG in the acinar carcinoma being negative in the IDC-P). In the second case, the foci of adenocarcinoma were distant from the IDC-P. The first patient had not biochemical recurrence after a 34 month follow-up period.
Conclusions: This kind of cases supports the existence of an infrequent subtype of IDC-P that could be considered as an in situ neoplasia.
Keywords: ERG; adenocarcinoma; intraductal carcinoma; prostate; prostate cancer.