435. A DIAGNOSTIC PITFALL; SMALL CELL CARCINOMA-LIKE FEATURES IN BASALOID SQUAMOUS CELL CARCINOMA OF THE ESOPHAGUS

Abstract Esophageal basaloid squamous cell carcinoma may resemble small biopsy specimens and cause difficulties in pathology diagnosis. We aimed to explore the pathological features of carcinomas that mimic clarify their diagnostic prognostic features. This study will contribute draw attention an important pitfall diagnosis endoscopic esophagus. Thirty esophageal were reviewed compared with 13 matched surgical specimens. A carcinoma-like feature was defined as, when at least one three following findings observed: 1) diffuse growth pattern, 2) nuclear molding 3) crush artifact. Immunohistochemistry synaptophysin, chromogranin A, CD56 (neuroendocrine markers) p16 performed all cases. Small features, such as growth, molding, or artifact, identified 80% (24/30) biopsies 77% (10/13) surgery specimens, but a proportionally much smaller area than samples. The presence had no impact on patients´ outcome. Immunohistochemically, synaptophysin consistently negative, while expressed 42% (10/24) p16, highly sensitive marker for carcinoma, also 8% (2/24). In conclusion, are frequent conspicuous biopsies, which probably be caused by exogenous factors friction external pressure occur procedure tumor environment. lead misinterpretation true if is only neuroendocrine expressed. expression detected carcinoma.