Colonic Endoscopic Submucosal Dissection for a Granular Cell Tumor with Insufficient Endoscopic Manipulation in the Hepatic Flexure

This report describes a granular cell tumor (GCT) with insufficient endoscopic manipulation in the hepatic flexure (HF) of the colon, which was treated by endoscopic submucosal dissection (ESD) using a splinting tube and the spring S-O clip traction method. A 44-year-old man presented with a 10 mm subepithelial tumor in the HF near the ascending colon on colonoscopy. The lesion had a smooth surface without erosion. The histology of biopsied specimen from the lesion was suspected as a GCT. Most GCTs are considered low-grade malignant, but ESD was chosen to treat the lesion due to the patient's insistence on endoscopic treatment. Because the lesion was located in the HF, it was assumed that the scope manipulation during ESD would be difficult. During ESD, a splinting tube was utilized to stabilize endoscopic manipulation and the spring S-O clip traction method to keep clear visualization of the submucosa, and the procedure was completed without adverse events. An 8 × 7 mm lesion with negative margins was removed by ESD. Hematoxylin and eosin staining showed atypical cells with round-to-oval nuclei and acidophilic vesicles, and immunohistochemical staining for S-100 protein was strongly positive with a Ki-67 labeling index of 5%. The lesion was pathologically confirmed as a GCT. This case showed the usefulness and safety of ESD for GCT with insufficient endoscopic manipulation in the HF.