Introduction

Colonic schwannoma is an extremely rare neurogenic tumor of the gastrointestinal tract, often presenting as incidental finding or with nonspecific gastrointestinal symptoms. The diagnosis can be challenging due to overlapping endoscopic and imaging features with other subepithelial lesions. Traditional management has relied on surgical resection, yet advances in endoscopic techniques have enabled minimally invasive alternatives. We report two cases of colonic schwannoma successfully managed by Endoscopic Full-Thickness Resection(EFTR).

Case Report 1 

A 66-year-old man with a medical history of arterial hypertension and pacemaker under aspirin therapy was referred to our department due to an asymptomatic suspected subepithelial lesion, incidentally found during an outpatient screening colonoscopy, with inconclusive biopsy results. Endoscopy ultrasound showed a 12*10-mm heterogeneous hypoechoic lesion arising from the submucosal layer.   After multidisciplinary discussion, a minimally invasive endoscopic resection was proposed by Endoscopic Submucosal Dissection (ESD). During colonoscopy, a 12-mm subepithelial lesion was identified at the proximal sigmoid colon with superficial erosion. During the clip-band traction-assisted ESD, the involvement of  muscularis propria layer was observed leading to a switch for EFTR using the colonic FTRD® system (Ovesco Endoscopy, Tubingen, Germany). A transmural en-bloc resection was achieved with no complication. Histopathological analysis revealed a R0-resection of a S-100 positive spindle-cell tumor, compatible with a reticular/microcystic-type schwannoma.

Case Report 2 

A 60-year-old woman with a medical history of arterial hypertension was referred to our department for evaluation of an asymptomatic subepithelial lesion, incidentally identified during an outpatient screening colonoscopy. It was decided for minimally invasive endoscopic resection at multidisciplinary meeting. A 10-mm yellowish and firm-elastic subepithelial lesion at the cecum with no involvement of appendix was observed in the therapeutic colonoscopy, with non-lifting sign. An EFTR was attempted with an en-bloc transmural resection of the lesion after being grasped into the cap using the colonic FTRD® system, with no complications. A schwannoma was diagnosed on histopathological examination with positivity for S-100, SOX-10 and CD-68.

Conclusion 

EFTR proved to be an effective and safe minimally invasive approach for the management of small colonic schwannomas regardless colonic location. EFTR may represent a valuable alternative to conventional surgical resection for selected patients with subepithelial colonic tumors up to 20/25-mm, depending on the lesion consistency and the presence of fibrosis.