Concordance of lymphovascular invasion diagnosed in penile carcinoma with and without the immunohistochemical markers ERG and CD31.

Lymphovascular invasion (LVI) is an independent predictor of metastatic lymph node disease in penile carcinoma and is one factor used to guide clinical management. The presence of LVI with and without the use of the endothelial immunohistochemical (IHC) markers, ERG and CD31, was retrospectively assessed in 46 penectomy cases containing invasive penile carcinoma (43 squamous cell carcinoma and 3 non-squamous cell carcinoma). Concordance for the detection of LVI between the original report, upon pathology review, and with the use of IHC was determined and histologic pitfalls were identified. For penile squamous cell carcinoma, LVI was diagnosed in 27.9% of tumors in the original reports, 16.3% upon pathology review, and in 16.3% with use of ERG and CD31. Concordance of LVI identification in the original report compared to IHC was 74.4% while concordance of review compared to IHC was 95.3%. Using IHC data as the reference, false positive LVI diagnoses were more common in the original report than false negatives. Histologic mimickers of LVI including involvement of the penile corpora cavernosum or spongiosum vasculature, seromucinous colonization, and a nested pattern of tumor invasion were identified. We demonstrated that it was not uncommon for LVI in penile carcinoma to be overdiagnosed or underdiagnosed. The use of endothelial IHC markers, such as ERG or CD31, or additional pathology consultation is recommended for penectomy cases in which LVI is difficult to histologically discern.