Endoscopic Submucosal Dissection of a Colonic Calcifying Fibrous Tumor

A 49-year-old woman was referred to our hospital for further treatment due to the suspicion of a submucosal tumor in a routine screening colonoscopy. On colonoscopy, a 1-cm sized subepithelial mass with normal overlying mucosa in the hepatic flexure was found. Endoscopic ultrasonography (EUS) showed a homogenous hypoechoic lesion arising from the second and third layer. We were unable to make a final diagnosis because the lesion showed a small tumor with atypical macroscopic morphology including EUS findings. Therefore, endoscopic submucosal dissection was performed for the diagnostic treatment of the tumor. Submucosal dissection was performed just above the muscle layer, and the tumor was removed completely and reliably without any acute complications such as perforation. Based on histopathological findings, we diagnosed a benign, calcifying fibrous tumor (CFT). The present case is the first report of successful endoscopic diagnosis and treatment of colonic CFT mimicking a submucosal tumor. Clin Endosc 2020;53:487-490