[Diagnostic criteria of prostatic carcinoma]

The histological diagnosis of prostate cancer relies on a combination of structural and cytological findings. Structural features are assessed at low power magnification. Malignant glands are recognised by their abnormal size, shape and location in relation to the surrounding benign glandular structures. The presence of pathological intraluminal secretions (pink amorphous secretions, crystalloids, blue-tinged mucinous secretions) is always suspicious, but not diagnostic for prostate cancer. Cytological criteria including nuclear and nucleolar enlargement, hyperchromasia and cytoplasmic changes have to be evaluated in comparison with the cytological features of surrounding benign glands. The presence of prominent nucleoli is neither diagnostic for malignancy nor represents an absolute requirement for the diagnosis of prostate cancer. The basal cell layer is absent in invasive adenocarcinoma, an important feature that has to be evaluated with care since benign glands may also lack detectable basal cells. The immunohistochemical demonstration of basal cells with high molecular weight cytokeratins excludes invasive cancer. This article reviews the histological criteria for the diagnosis of prostate cancer, including variants of common adenocarcinoma and therapy-induced changes.