Adenoid Cystic/Basal Cell Carcinoma of the Prostate: Review and Update

Context.—Although most prostate carcinomas are of the conventional acinar type, unusual variants have been reported. Adenoid cystic/basal cell carcinoma of the prostate is a rare tumor with distinctive histopathologic features. There are only a few publications in the literature concerning the diagnosis, treatment, and prognosis of this neoplasm. Objective.—To review current literature together with the clinical, pathologic, and immunohistochemical features of adenoid cystic/basal cell carcinoma of the prostate and offer a practical approach to the diagnosis—including the differential diagnosis—of this neoplasm in surgical pathologic specimens. Data Sources.—Adenoid cystic/basal cell carcinoma of the prostate is composed of infiltrating basaloid cells forming dilated acinar and cribriform spaces with luminal basementlike material. Differentiation of adenoid cystic/basal cell carcinoma from basal cell hyperplasia and cribriform pattern of acinar adenocarcinoma may be difficult. The use of cytokeratin 34βE12 and prostate-specific antigen can help in difficult cases. Most cases are indolent, but metastasis has been documented in a few cases. Conclusions.—Various histologic and immunohistochemical features are helpful in recognizing adenoid cystic/basal cell carcinoma of the prostate. This is a rare subtype of prostate cancer and correct diagnosis is important because of the unique clinical and biological features and the implications for treatment and prognosis.