EUS demonstration of nonlifting sign in a dysplastic polyp at the appendiceal orifice

Abstract

An 85-year-old man underwent colonoscopy and was found to have a flat polyp at the appendiceal orifice. Biopsy specimens revealed a tubular adenoma with high-grade dysplasia (HGD). The patient was referred for endoscopic resection. A 1-cm horseshoe-shaped flat polyp was found (Fig. 1A; Video 1, available online at www.giejournal.org). EUS was performed with the 20-MHz miniprobe, revealing a hypoechoic lesion arising from the mucosa and invading the submucosa (Fig. 1B). Submucosal injection of a dilute indigo carmine solution resulted in a nonlifting sign, consistent with submucosal invasion (Fig. 1C).