[MALT (Mucosa-Associated Lymphoid Tissue) Lymphoma of the colon]

Mucosa-Associated Lymphoid-Tissue Lymphoma of the Cecum and Rectum: A Case Report

A colonic mucosa-associated lymphoid-tissue (MALT) lymphoma is relatively rare compared to lymphomas of the stomach or small intestine. We present a case of a MALT lymphoma in the cecum and rectum found during screening colonoscopy. A 54-year-old female, who had undergone right-breast-conserving surgery with axillary dissection due to an invasive ductal carcinoma and a left-breast excisional biopsy due to microcalcification following adjuvant chemoradiation therapy 3 years earlier, was found to have 3-mm-sized smooth elevated lesions in both the cecum and rectum. No pathologic lesion or lymphadenopathy was found at any other site, but chronic gastritis negative for Helicobacter pylori infection was found. The polyps were removed by using an endoscopic biopsy and revealed an extra nodal marginal zone B-cell MALT lymphoma, showing positive for CD3 and CD20 by immunohistochemical staining. The patient underwent close observation without any additional treatment and has shown no evidence of recurrence as of her last visit.

Regression of Cecal MALT Lymphoma after Antibiotic Treatment in a Patient with Helicobacter pylori Infection

A 63-year-old man with abdominal discomfort was referred to our hospital. Colonoscopy revealed a hemispherical-shaped protruding cecal mass of approximately 10 mm in size with a normal mucosal surface. Biopsy specimens showed nodules consisting of the proliferation of atypical lymphoid cells. Mucosa-associated lymphoid tissue (MALT) lymphoma was diagnosed based on the histological and immunohistochemical findings. Since upper gastrointestinal endoscopy demonstrated Helicobacter pylori-associated atrophic gastritis, eradication therapy was administered. The cecal mass disappeared completely within three months after triple therapy. Therefore, H. pylori eradication therapy may be a useful treatment option for cecal MALT lymphoma.

A case of mucosa-associated lymphoid tissue lymphoma of the sigmoid colon presenting as a semipedunculated polyp

Mucosa-associated lymphoid tissue (MALT) lymphomas are characterized by lymphoepithelial lesions pathologically. Colonic MALT lymphomas are relatively rarer than lymphomas of the stomach or small intestine. Endoscopically, colonic MALT lymphoma frequently appears as a nonpedunculated protruding polypoid mass and/or an ulceration in the cecum and/or rectum. We report a unique case of a colonic MALT lymphoma presenting as a semipedunculated polyp. A 54-year-old man was found to have a 2-cm semipedunculated polyp in the sigmoid colon during screening colonoscopy. The polyp was removed by endoscopic mucosal resection. Histologic examination of the resected polyp revealed diffuse epithelial infiltration by discrete aggregates of lymphoma cells. We diagnosed the tumor as low-grade B-cell MALT lymphoma by immunohistochemical staining.