Pseudobenign prostate carcinomas: causes of false-negative biopsy results

Prostate carcinomas are continuously surprising the pathologists through their multitude of variants and histological subtypes, some of them being recently described and characterized. Among these are individualized: atrophic carcinoma, foamy gland, pseudohyperplastic, microcystic, certain subtypes of ductal adenocarcinoma and hormone-treated adenocarcinoma, which because of minimal architectural and/or cytological atypia are often under-diagnosed, especially in small tissue fragments. This paper presents the morphological criteria, including information provided by some immunohistochemical markers for positive and differential diagnosis of these variants/subtypes of prostate adenocarcinoma with which the pathologist should be familiar and avoid their confusion with a series of similar histological structures or benign/premalignant lesions.