Contemporary update on pathology-related issues on routine workup of prostate biopsy: sectioning, tumor extent measurement, specimen orientation, and immunohistochemistry.

Abstract

While the prime goal of the needle biopsy is to diagnose prostatic adenocarcinoma (PCa), once PCa is detected further descriptive information regarding the type of cancer, amount of tumor, and grade in prostate needle cores forms the cornerstone for contemporary management of the patient and to assess the potential for local cure and the risk for distant metastasis. This review gives an update on selected pathology-related issues on routine workup of prostate biopsy with special references to adequate histologic sectioning necessary to maximize cancer yield, tumor extent measurements and methodologies, specimen orientation, and the role of immunohistochemistry in the evaluation of the prostate. Multiple factors influence the diagnostic yield of prostate biopsies. Many of these factors are fixed and uncontrollable. Other factors are controlled by the urologist, including number of cores obtained, method and location of biopsy, and amount of tissue obtained. The yield of cancer is also controlled by the pathologist and histotechnologist. It is necessary to report the number of cores submitted and the number of positive cores, thereby giving the fraction of positive cores. The percentage involvement by carcinoma with or without the linear extent of carcinoma of the single core with the greatest amount of tumor should also be provided. Using the marking technique, we can add a new pathological parameter: pathological orientation. Cancer or atypical lesions can be accurately located within the biopsy specimen and integrated to biopsy approach. Probably the most common use of immunohistochemistry in the evaluation of the prostate is for the identification of basal cells, which are absent with rare exception in adenocarcinoma of the prostate and in general positive in mimickers of prostate cancer. If a case is still considered atypical by a uropathology expert after negative basal cell staining, positive staining for alpha-methylacyl-CoA-racemase can help establish in 50% of these cases a definitive diagnosis of cancer.