Published online Jun 6, 2021. doi: 10.12998/wjcc.v9.i16.3988
Peer-review started: January 2, 2021
First decision: January 27, 2021
Revised: January 31, 2021
Accepted: March 9, 2021
Article in press: March 9, 2021
Published online: June 6, 2021
Processing time: 131 Days and 18.9 Hours
Colorectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease, and only a few cases have been reported to date. It has no specific clinical presentations and shows various endoscopic appearances. There is no uniform consensus on its treatment. With the advancement of endoscopic technology, endoscopic treatment has achieved better results in individual case reports of early-stage patients.
We report a case of rectal MALT in a 57-year-old Chinese man with no symptoms who received endoscopy as part of a routine physical examination, which incidentally found a 25 mm × 20 mm, laterally spreading tumor (LST)-like elevated lesion in the rectum. Therefore, he was referred to our hospital for further endoscopic treatment. Complete and curable removal of the tumor was performed by endoscopic submucosal dissection. We observed enlarged and dilated branch-like vessels similar to those of gastric MALT lymphoma on magnifying endoscopy with narrow-band imaging. And immunopathological staining showed hyperplastic capillaries in the mucosa. Histopathological findings revealed diffusely hyperplastic lymphoid tissue in the lamina propria, with a visible lymphoid follicle structure surrounded by a large number of diffusely infiltrated lymphoid cells that had a relatively simple morphology and clear cytoplasm. In addition, immunohistochemical analysis suggested strongly positive expression for CD20 and Bcl-2. Gene rearrangement results showed positivity for IGH-A, IGH-C, IGK-B, and IGL. Taking all the above findings together, we arrived at a diagnosis of extranodal marginal zone B-cell lymphoma of MALT lymphoma. Positron emission tomography-computed tomography examination showed no other lesions involved. The patient will be followed by periodic endoscopic observation.
In conclusion, we report a case of rectal MALT with an LST-like appearance treated by endoscopic submucosal dissection. Further studies will be needed to explore the clinical behavior, endoscopic appearance, and treatment of rectal MALT.
Core Tip: Compared to mucosa-associated lymphoid tissue (MALT) in the stomach, primary rectal MALT lymphoma remains a rare disease. There are no representative clinical symptoms or endoscopic features reported in the literature. We report a case of rectal MALT lymphoma with a laterally spreading tumor-like appearance. The lesion presented enlarged and dilated vessels on the surface. Endoscopic submucosal dissection was performed. The histopathological and immunohistochemical findings led to a diagnosis of rectal MALT lymphoma.