Endoscopic removal of large colonic lipomas: difficult submucosal dissection or easy snare unroofing?

We read with interest the article by Okada et al. [1] on endoscopic submucosal dissection (ESD) of a large submucosal lipoma in the colon. Although the lipoma was successfully resected en bloc by ESD without complication, we recommend endoscopic snare unroofing instead of ESD in this patient.

Colonic lipomas, rare benign adipose tumors, can be diagnosed during colonoscopy based on a fatty-yellow color in appearance and eliciting the ”cushion or pillow sign” and ”naked fat sign” [2] [3] [4] [5]. Although most lipomas remain asymptomatic and need no treatment, large lipomas can cause symptoms including pain, diarrhea, obstruction, bleeding, and intussusception [2] [3] [4] [5]. Removal of such tumors is indicated, and endoscopic removal would be preferable to surgery [4].

Endoscopic removal of large lipomas carries the increased risk of bleeding or perforation with technical difficulties [2] [3] [4] [6]. Fatty tissue does not conduct electricity well, and soon it becomes impossible to bring the snare through the base [7]. Large colonic lesions occlude the intestinal lumen, which makes it difficult to snare over the lesions [4]. For safe endoscopic removal of large lipomas, experiences with the assistance of endoscopic ultrasonography [3] [5] [8], clip [7], and/or submucosal injection of saline or epinephrine [9] have been reported. We and others have also applied an endoloop, which has the most advantage by securing the base of elevations before transection [2] [3] [4] [6].

In recent advances in endoscopic therapy, the ESD method increases the rate of complete en bloc resection of large gastric mucosal cancers with large mucosal defect; however, it is technically difficult and accompanied by a high risk of complications [10]. Although ESD also reduces the local recurrence rate, a long procedure time and a high incidence of bleeding and perforation remain problems [10]. Okada et al. [1] successfully removed the lipoma by ESD technique but we believe that ESD could be dangerous and requires advanced endoscopic skills when performed within the colonic lumen, a thin-walled structure. Endoscopic removal with tumor-free margins is required for early malignant tumors but not for the benign nature of lipomas.

Large lipomas are also successfully managed by the endoscopic unroofing technique that only cuts off the upper half of the submucosal tumor, thus preventing perforation [5] [8]. The yellowish adipose tissue rapidly exudes from the cut surface, resulting in a scarred mucosa without any residual lipoma after elimination of the remaining adipose tissue. The unroofing technique allows both histological confirmation and treatment with minimum mucosal injury. Large lipomas can apparently be eliminated safely and completely by simply removing their top without requiring complete resection. We therefore believe that endoscopic snare unroofing is easy, safe, and sufficient for the treatment of large lipomas, and ESD might be more difficult, dangerous, and time consuming compared with the unroofing technique.

Competing interests: None

References

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