Mimickers of Prostate Cancer: From Adenosis to Xanthoma

Context.— Mimickers of prostate cancer are more common than prostate cancer itself. Variation of normal in benign prostate is probably more prevalent than in any other human organ. Distinction of mimickers from cancer and vice versa is a common challenge in prostate tissue interpretation. Objective.— To summarize our approach to this challenging topic and provide some suggestions for the key morphologic features and immunohistochemistry findings that are used to properly classify these benign findings. Data Sources.— Personal experience, including original description of the entities, their diagnostic criteria, and immunoprofile; observation of challenges in pathologist-driven consultation; and thorough literature review. Conclusions.— Depending on the experience of the interpreter, some of these mimickers have less similarity with cancer on hematoxylin-eosin and proper immunohistochemistry. However, several benign histologic lesions are more challenging and have closer morphology and immunohistochemistry overlap with prostate cancer. For practical purposes, it is wise to split mimickers into those reminiscent of a lower Gleason pattern versus those that simulate a high-grade pattern. As is true for all prostatic cancer mimickers, clinical (eg, presence on transurethral resection of the prostate or biopsy), morphologic, and immunohistochemical findings need to be integrated for diagnosis, as any of these findings in isolation may be concerning for prostate cancer. Mimickers of prostate cancer have not been linked to direct progression to prostate cancer and are not actionable by urologists.