Multifocal colonic mucosa-associated lymphoid tissue lymphoma with synchronous tubular adenoma: a coincidental association?

Abstract

Dear Editor: Primary colorectal lymphoma is a rare condition, accounting for 10% to 20% of all gastrointestinal lymphomas and 0.2% to 0.6% of all large bowel malignancies. Most colonic lymphomas are non-Hodgkin's lymphomas and include diffuse large B-cell lymphoma, follicular lymphoma, small lymphocytic lymphoma, Burkitt's lymphoma, and mantle cell lymphoma. Mucosa-associated lymphoid tissue (MALT) lymphoma is one of the less common histological types and is mostly restricted to one segment of colon. We herein present a case of multifocal colonic MALT lymphoma, with concomitant tubular adenoma, with undistinguishable endoscopic features. A 52-year-old man was referred to our department after colonic polyps were diagnosed in a screening colonoscopy. He was asymptomatic, and his past medical history was irrelevant. His mother died at the age of 72 due to colorectal cancer, and his 54-year-old brother had already been treated for the same condition. Physical examination was unremarkable. Total colonoscopy was performed, revealing three polypoid lesions: two sessile polyps, measuring 15 mm, located in the transverse and descending colon; and a pedunculated polyp, measuring 12 mm in the sigmoid colon. En bloc snare polypectomy of all polyps was performed without complications. Histological study of both sessile polyps revealed colonic mucosa with marked expansion of the lamina propria by atypical lymphoid cells, of small to intermediate size and irregular nucleus with dense chromatin. Sparse lymphoepithelial lesions were also observed. On immunohistochemistry, tumor cells were positive for CD20, CD79a, and BCL2, but negative for CD5, CyclinD1, CD10, and CD23 markers. A diagnosis of MALT lymphoma was made. The pedunculated polyp was a tubular adenoma with low-grade dysplasia. Based on this unexpected information, staging work-up was performed. β2-microglobulin titer was within normal range. Whole-body computed tomography (CT) scan showed neither lymphadenopathy, nor involvement of the liver or spleen. Bone marrow biopsy and aspirate were normal. Upper endoscopy revealed no remarkable findings. Gastric biopsy specimens from antrum and corpus showed no signs of lymphoma and were positive for Helicobacter pylori (H. pylori) infection. Based on these findings, a final diagnosis of primary extranodal MALT lymphoma stage IE-A from modified Ann Arbor staging system was made. The patient was treated with H. pylori eradication therapy (esomeprazole–amoxicillin–clarithromycin) and 6 cycles of chemotherapy (cyclophosphamide, vincristine, adriamicine, prednisolone, and rituximab). Three months later, a urea breath test was negative, and a follow-up colonoscopy showed no signs of disease. R. Ferreira (*) : J. Torres :M. J. Pereira : J. Carvalheiro : S. Mendes :M. Ferreira : C. Agostinho :M. J. Campos Gastroenterology Service of the Hospitalar Center of Coimbra, Coimbra, Portugal e-mail: rosa.l.ferreira@gmail.com