D2-40 INCREASES DETECTION OF LYMPHATIC INVASION IN BREAST CARCINOMA

Kyle L Eskue, M.D., M.Eltorky, M.D., Ph.D., B. Mohammad, M.D.

Department of Pathology, UTMB

Background: Detection of lymphatic invasion is an important component of complete histopathologic evaluation of primary breast carcinoma for accurate determination of prognosis and management. Failure to identify legitimate lymphatic invasion and detection of artifactual lymphatic spaces caused by tissue retraction around tumor are diagnostic pitfalls facing Pathologists. Objective: We hypothesized that using D2-40 antibody, a sensitive marker for lymphatic endothelium, can increase the sensitivity of detecting true lymphatic invasion in breast carcinoma. Methods: Sixteen cases of lymph node-positive, invasive breast carcinoma that were negative for identification of lymphovascular invasion on H&E sections, were retrospectively collected. Tissue blocks were selected for D2-40 immunostaining and cases with unequivocal tumor emboli within positively stained, endothelial-lined lymphatic vessels were counted as positive. Results: Four out of the sixteen cases (25%) showed definitive lymphatic invasion within tissue sections that were previously unidentified by H&E stained slides alone. Conclusions: D2-40 immunostain increases the diagnostic sensitivity of lymphatic invasion detection in cases of primary breast carcinoma. The study also demonstrates the usefulness of D2-40 immunostain as a tool to confirm or reject suspected foci of lymphatic invasion that are questionable in H&E stained slides.