Successful endoscopic resection using a bipolar snare for an adenoma overlying a transverse colonic lipoma

Colonic lipomas are uncommon mesenchymal neoplasms, and the transverse colon appears to be the rarest site for colonic lipomas [1]. Furthermore, it is rare to have an adenomatous polyp growing over the mucosal surface of a colonic lipoma.

A 72-year-old man was referred to our hospital from a private clinic for a colonic polyp overlying a submucosal tumour (SMT). The biopsied specimen taken at the private clinic revealed a tubular adenoma with fatty tissue. Endoscopy showed a type 0-IIa polyp, 12 mm in diameter, overlying a sessile SMT, with the mass having a positive cushion sign, in the transverse colon ([Fig. 1 a]). Magnifying narrow-band imaging revealed regular vessels and surface patterns ([Fig. 1 b]); therefore, we diagnosed an adenoma overlying a lipoma. We successfully performed hot snare polypectomy with a bipolar electrode ([Video 1]), and naked fat was visible at the base of the resection site ([Fig. 1 c]). There were no adverse events. Histological examination showed a tubular adenoma with low grade dysplasia and the fatty tissue was compatible with a lipoma ([Fig. 2]).

Fig. 1 Endoscopic images showing: a a type 0-lla polyp overlying a sessile submucosal tumour in the transverse colon; b narrow-band imaging revealing regular vessels and surface patterns; c visible naked fat at the base of the resection site.

Video 1 Successful endoscopic resection using bipolar snare for adenoma overlying a transverse colonic lipoma.

Fig. 2 Pathological findings showing: a a tubular adenoma with low grade dysplasia on fatty tissue; b a lipoma beneath the tubular adenoma.

Endoscopic polypectomy of a colonic lipoma with a monopolar electrode is known to carry a risk of perforation as the lipomatous tissue has a low water content and therefore conducts electrosurgical current less efficiently [2]. Therefore, increasing the power to assist endoscopic resection may damage the adjacent bowel wall with subsequent perforation [3]. Placing an endoloop prior to an endoscopic resection can prevent perforations [4]; however, in our case, the shape of the SMT was sessile, meaning the endoloop wire would slip during closure so could not be placed. With the bipolar instrument, the electric current only flows from the snare toward a sheathed electrode, thereby avoiding deep thermal injury [5]. As a result, we were able to simply and safely resect the adenoma overlying the colonic lipoma using a bipolar snare, without any perforation.

Endoscopy_UCTN_Code_TTT_1AQ_2AD

Publication History

Article published online:
27 March 2020

• References

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