Prostate cancer is a major public health problem throughout the developed world. For patients with clinically localised
prostate cancer, the diagnosis is typically established by histopathological examination of prostate needle biopsy samples. Major and minor criteria are used to establish the diagnosis, based on the microscopic appearance of slides stained using haematoxylin and
eosin. Major criteria include an infiltrative glandular growth pattern, an absence of basal cells and nuclear atypia in the form of nucleomegaly and nucleolomegaly. In difficult cases, basal cell absence may be confirmed by immunohistochemical stains for high-molecular-weight cytokeratins (marked with antibody 34betaE12) or p63, which are basal cell markers. Minor criteria include intraluminal wispy blue
mucin, pink amorphous secretions, mitotic figures, intraluminal crystalloids, adjacent high-grade
prostatic intraepithelial neoplasia, amphophilic cytoplasm and nuclear hyperchromasia. Another useful diagnostic marker detectable by immunohistochemistry is alpha-methylacyl
coenzyme A racemase (AMACR), an
enzyme selectively expressed in neoplastic glandular epithelium. Cocktails of
antibodies directed against basal cell markers and AMACR are particularly useful in evaluating small foci of atypical glands, and in substantiating a diagnosis of a minimal
adenocarcinoma. Reporting of
adenocarcinoma in needle biopsy specimens should always include the Gleason grade and measures of tumour extent in the needle core tissue. Measures of tumour extent are (1) number of cores positive for
cancer in the number of cores examined, (2) percentage of needle core tissue affected by
carcinoma and (3) linear millimetres of
carcinoma present.