Gastrointestinal stromal tumor of the colon - endoscopic treatment by full-thickness resection.

A 51-year-old man was referred for therapy of a submucosal tumor of the sigmoid colon. The lesion had been diagnosed during screening colonoscopy, and biopsies had shown gastrointestinal stromal tumor (GIST). We confirmed a 15-mm submucosal tumor located in the proximal sigmoid colon (●" Fig.1). Endoscopic full-thickness resection was performed with the Full Thickness Resection Device (FTRD; Ovesco Endoscopy, Tübingen, Germany) (●" Fig.2,●" Video 1). The FTRD system and first clinical experience were recently described by Schmidt et al. [1]. The resection was performed while the patient was under conscious sedation with midazolam and propofol. The procedure time was 25 minutes, and the remainder of the coursewas uneventful. Histologic analysis of the 30-mm specimen confirmed full-thickness resection of the colonic wall, which contained a 12-mm GIST originating from the muscularis propria layer (●" Fig.3). The resected GIST specimen was R0 and showed 2 mitoses/5mm2. The resection was judged to be curative, and the patient was followed without further treatment. GISTs of the colon are rare. In a large study of 4411 GISTs, the stomach was the predominant location (60.3%); colonic lesions accounted for only 2.9% and rectal lesions for another 3.1% [2]. For gastric GISTs, several endoscopic resection techniques have been reported, including full-thickness resection with or without laparoscopic hybrid techniques [3]. For colonic GISTs originating from themuscularis propria layer, surgical resection has usually been needed to date to achieve complete resectionwithout perforation [4]. After the introduction of the over-thescope clip (OTSC; Ovesco Endoscopy), endoscopic full-thickness resection in the colorectum became possible. A “pseudopolyp” containing the complete colonic wall is created with application of the OTSC, and snare resection of the pseudopolyp is performed afterward [5]. The novel FTRD system allows endoscopic full-thickness resection of colorectal lesions in one step. Endoscopic resection with the FTRD system should be considered the treatmentof choice for small colorectal submucosal tumors when resection is needed (e.g., when GIST is confirmed or when the histology is unknown).