Endoscopic diagnosis of gastrointestinal melanoma

Background: Gastrointestinal (GI) melanoma can be diagnosed by endoscopy combined with biopsy and subsequent pathological examination. However, the disease may be misdiagnosed due to the limited awareness of GI melanoma. Objective: We aimed to describe characteristics of GI melanoma that can be detected by endoscopy and endoscopic ultrasound (EUS). Methods: We retrospectively analyzed patients with GI melanoma diagnosed by endoscopic biopsy or postoperative pathology between August 2008 and January 2017. Images of endoscopic examinations, including endoscopy and EUS, were reviewed to characterize GI melanomas. Results: A total of 21 patients (9 males, 12 females) with GI melanoma were enrolled in this study. Several types of melanoma were identified: anorectal melanoma (n = 15), esophageal melanoma (n = 3), gastric melanoma (n = 2), and melanoma of the small intestine (n = 1). EUS was performed for one case of esophageal melanoma, one case of gastric melanoma, and seven cases of anorectal melanoma. Conclusions: GI melanoma is a rare disease. Most GI melanomas showed typical endoscopic manifestations, including black plaques. EUS is a reliable tool for evaluating the depth of infiltration of GI melanoma.