Contemporary Updates on Subtypes of Prostate Cancer.

Context.—: Prostatic acinar adenocarcinoma is the most common type of prostate cancer, while other types of cancer infrequently involve the prostate. In this review, we present an overview of contemporary updates on all types of cancers involving the prostate, with a focus on subtypes of prostatic adenocarcinoma. Unusual histological patterns and subtypes of acinar adenocarcinoma, and non-acinar forms of prostate cancers, and their prognostic and therapeutic relevance are discussed. The following summary of the contents presented in part at the 12th Princeton Integrated Pathology Symposium, Plainsboro, New Jersey, on May 10, 2025, supplemented with a relevant literature review, exemplifies the common diagnostic challenges and pitfalls for subtypes of prostate cancer, with emphasis on immunohistochemical and molecular updates when relevant. Objective.—: To describe the common lesions in the prostate, with emphasis on the diagnostic challenges and pitfalls that may arise in the pathologic assessment, and to highlight immunohistochemical workups and emerging molecular findings when relevant. Data Sources.—: Published peer-reviewed literature and personal experience are the sources for this study and presented at the course. Conclusions.—: Although most prostate cancers are acinar adenocarcinoma, other types of prostate cancer infrequently occur, which may pose diagnostic challenges. Pitfalls that arise in the pathologic assessment of prostate cancer should raise awareness. We summarize the course content, supplement it with a relevant literature review, and hope to provide a diagnostic framework for evaluating these lesions in routine clinical practice.