Rectal mucosa-associated lymphoid tissue lymphoma treated by endoscopic submucosal resection with band ligation

A 75-year-old woman presented with a positive fecal occult blood test. She had no previous personal or family history of malignancy. Colonoscopy revealed a slightly yellowish 6-mm protrusion in the rectum resembling a submucosal tumor (SMT) (Fig. 1A). Narrow-band imaging showed dilated vessels with branching architectures on the surface and a nonstructural area (Fig. 1B), suggestive of mucosa-associated lymphoid tissue (MALT) lymphoma. However, the color of the lesion was indicative of a carcinoid tumor, which was therefore suspected. Owing to the overlapping features of MALT lymphoma and carcinoid tumor, optical diagnosis of the SMT-like protrusion would be of low confidence. Therefore, it was removed by endoscopic submucosal resection with band ligation (ESMR-L) for diagnosis and treatment (Fig. 1C). Histopathologic examination showed diffuse infiltration of monotonous small-sized lymphoid cells in the mucosa (Fig. 2), positive for CD20 but negative for CD3 and CD10. The lesion was diagnosed as rectal MALT lymphoma. The resected margin was negative. The patient recovered with no complications and remains in complete remission at the five-year follow up