Benign mesothelial inclusions in pelvic lymph nodes may be mistaken for metastatic disease in the setting of pelvic malignancy. In this case-report a patient with Low-Risk prostate cancer (confirmed by biopsy and genomic testing) underwent radical prostatectomy with pelvic lymph node dissection. The initial pathological diagnosis was organ-confined Gleason 3 + 3 = 6 cancer with metastasis to a pelvic lymph node. Upon review of the pathological specimen and immunohistochemical staining the lymph node tissue concerning for metastatic disease was recharacterized as mesothelial in origin. This case illustrates the importance of second opinions and immunohistochemistry for unexpected or unusual pathological findings.

Prostate cancer (CaP) will be diagnosed in approximately 181,000 American men in 2016. Despite the high number of deaths from CaP in the United States, the disease has a protracted natural history and many men diagnosed with CaP will not die of the disease regardless of treatment. Unfortunately, identification of men with truly indolent/ nonaggressive CaP is challenging; limitations of conventional diagnostic modalities diminish the ability of physicians to accurately stage every case of CaP based on biopsy results alone. The resulting uncertainty in prognosis may prompt men with low-risk CaP to proceed to morbid and expensive treatments for an unclear survival benefit. Incorporation of the Genomic Prostate Score (GPS) as part of the decision algorithm for patients with National Comprehensive Cancer Network very low-risk and low-risk cancer led to a substantial increase in uptake of active surveillance and substantial cost savings. GPS provides physicians and patients with an additional tool in assessing personalized risk and helps guide individual decision making.