Copyright ©The Author(s) 2023.
World J Gastrointest Endosc. May 16, 2023; 15(5): 319-337
Published online May 16, 2023. doi: 10.4253/wjge.v15.i5.319
Table 1 Endoscopic ultrasonography features of subepithelial tumors
Subepithelial tumor
Endoscopic ultrasound layer
Histological layer
Other features
Gastrointestinal stromal tumor 4thMuscularis propriaHypoIrregular or roundHeterogenous, marginal halo, cystic spaces, lymphadenopathy
Leiomyoma 2nd or 4thDeep mucosa or muscularis propriaHypoRoundHomogenous, fine margins
Neuroendocrine tumor (carcinoid) 2ndDeep mucosaHypo or isoRound, sessile or polypoidErythematous depression or ulceration, smooth margin
Lipoma 3rdSubmucosaHyperRoundHomogenous
Schwannoma 4thMuscularis propriaHypoRoundHeterogenous, exophytic
Granular cell tumor 2ndDeep mucosaHypoRoundHomogenous, fine margins
Inflammatory fibroid polyp 2ndDeep mucosaHypoIrregularHeterogenous, diffuse margins
Ectopic pancreas 2nd, 3rd or 4thDepending on layerMixedIrregularDuctal structure, anechoic microcysts
Table 2 Common endoscopic knives used for gastric endoscopic submucosal dissection
Endo knife type
Name (manufacturer)
Insulated tip knife IT knife (Olympus, Tokyo, Japan)Less risk of muscle layer injury and perforation due to ceramic insulated tip, more suitable for submucosal dissection. Can be used for hemostasisCannot be used for marking, precutting or injection. More difficult to maneuver. Pull-cut limits direction of incision. Cutting performance tends to deteriorate in cases with severe fibrosis such as ulcer scars. Lateral cutting is difficult as the ceramic tip at the distal end catches in the mucosa. Laying the knife down too much increases the risk of perforation
IT knife 2 (Olympus, Tokyo, Japan)Improved incision and cutting performance in lateral cutting and fibrotic tissue with three blades attached to the back of the insulated ceramic tip. Faster incision and cutting, shorter operating time compared to IT knife. Safer than dual knife for beginnersNeedle knife for marking, precutting and injection. Difficult to manipulate in cardia and greater curvature of upper body. Sharper than IT knife which may increase the risk of perforation if firm pressure or too much downward angle is used. Needs more gentle manipulation than IT knife
Needle knife Dual knife (Olympus, Tokyo, Japan)Easy to maneuver. Can be used for all steps of ESD: Marking, injection, incision, dissection and hemostasis. Offers more precise fine incision with better cutting performance on fibrotic tissue and ulcer scarHigher risk of perforation when dissecting close to the muscularis propria, especially since the tip of the electrode is exposed (not insulated)
Scissor knife SB knife (Sumitomo Bakelite, Tokyo, Japan)External insulation, curved blades to protect muscle layer with reduced risk of perforation for gastric lesions. Superior safety profile. Rotatable to adjust cutting line. Useful to cut the fibrotic tissue. Sufficient coagulation before incision to minimize bleeding. Suitable for traineesCannot control severe bleeding. Discontinuous cutting
Clutch cutter (Fujifilm, Japan)Scissor-type knife similar to SB knife. More secure incision. Serrated cutting edge enables more efficient bleeding control than SB knife. Better self-completion rates and shorter procedure times for gastric ESD by nonexperts than IT2, probably due to hemostatic efficacyThicker than SB knife, cannot make a sharp mucosal incision as SB knife
Waterjet knife Hybrid knife (Erbe, Germany)Waterjet knife with needleless injection. Multi-function probe, can be used for all steps of ESD. Shorter procedure time compared to non-waterjet knives. Lower risk of bleeding by water cushion. Three types with different functionalitiesRequires ERBEJET® 2 hydro surgery system. More costly
RFA knife Speedboat (Creo Medical, United Kingdom)Multi-function probe, integrated injection needle, able to complete the entire procedure with a single instrument. Only bipolar RFA knife in the market, no grounding needed. RF cutting with lower voltage and minimal bleeding. Microwave coagulation with possibly lower rates of post polypectomy syndrome. Potentially faster procedureRequires therapeutic scope with at least 3.7 mm accessory channel