A large pedunculated polyp was discovered incidentally during colonoscopic examination
in a 70-year-old Japanese woman. She had undergone the examination after a positive
fecal occult blood test. The polyp was located in the sigmoid colon and had a long
stalk and a large head. Its removal was considered to be technically demanding because
the head of the polyp nearly occluded the lumen of the colon, making it difficult
to maneuver a snare over the polyp. The stalk of the polyp was fully visible, however,
and we attempted endoscopic resection using an insulated-tip diathermy knife (KD-610L;
Olympus, Tokyo, Japan) (Figure [1]). First, we applied a long clip (HX-600 - 090L; Olympus) to the base of the stalk,
close to the colonic wall, in order to prevent polypectomy-associated bleeding. The
polyp stalk was then cut about 8 mm above the clip using the insulated-tip diathermy
knife (Figure [2]). Pure cutting current was used. No hemorrhage, perforation, or other complication
occurred. Histological evaluation of the resection specimen revealed a serrated adenoma.
Figure 1 Schematic showing endoscopic resection of a polyp using an insulated-tip diathermy
knife. a A long metal clip is opened and applied to the stalk of the polyp, close to the colon
wall. b The clip clamps the stalk. c The stalk above the clip is cut with an insulated-tip diathermy knife (IT). d The lesion is removed from.
Figure 2 Endoscopic view of the resection of a colorectal polyp using an insulated-tip diathermy
knife. a The knife (IT) is used to cut the stalk (St) 8 mm above the clip (C). b The polyp is removed without bleeding.
It is often difficult to remove large pedunculated colorectal polyps by endoscopic
polypectomy using standard snare techniques [1]
[2]. Our approach was to perform an endoscopic resection using an insulated-tip diathermy
knife which can be passed through the endoscope’s ordinary working channel. This knife
was developed in Japan for endoscopic mucosal resection of early gastric cancer [3]
[4]. It has a ceramic ball at its tip which prevents electrosurgical perforation by
the needle-knife tip. Using this knife, it was safe and easy to cut the stalk of the
polyp. Clipping the basal side of the stalk prior to cutting was vital for preventing
polypectomy-induced bleeding. To our knowledge, this is the first report of endoscopic
polypectomy using an insulated-tip diathermy knife. We believe this technique has
the potential to become the method of choice for removal of pedunculated colorectal
polyps when procedures involving snaring of the polyp head are not feasible.
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