A CASE OF MUCOSA ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMA IN THE COLON AND RECTUM

Abstract

We report a case of mucosa associated lymphoid tissue (MALT) lymphoma in the colon and rectum. The patient was a 46-year-old woman who was admitted to our hospital because of occult blood in the stool. Barium enema study showed flat elevated lesions in the cecam and lower rectum. Both lesions were 5×5 mm in diameter. On colonoscopic observation, tumors showed a glossy yellowish-white surface with central depression. Endoscopic mucosal resection (EMR) was performed for the purpose of diagnosis and treatment. The histopathology of resected specimens demonstrated medium sized lymphocytes with cleaved nuclei and invasion of abnormal lymphocytes into the epithelium. The abnormal lymphocytes were positive for L-26 and negative for UCHL-1 on immunological study. The patient was diagnosed as low-grade MALT lymphoma in the colon and rectum, and the depth of invasion of abnormal lymphocytes was estimated to submucosal layer. MALT lymphoma in the colon and rectum is rare. The prognosis for MALT lymphoma in the colon and rectum is good by treating adequate operation, but a standard treatment has not been established. The surgical tumor resection including EMR is done to treatment for MALT lymphoma at present. Furthermore, investigation of the long term prognosis is necessary.