Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma of the Rectum: Report of Two Cases
We have treated two patients with low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) arising in the rectum. A 70-year-old female with anal bleeding underwent local excision of a rectal polypoid mass (3.0 X 2.3 X 1.3 cm) transanally to preserve the sphincter muscle. Pathological findings showing partial invasion to the muscularis propria were indicative for prophylactic combinationchemotherapy (1 X CHOP). A 72-year-old male in whom positive occult blood was detected underwent a low anterior resection for three aphthoid ulcers (1.0-1.5 cm in diameter, submucosal invasion). Radically resected tumors in early stages should require no further treatment. However, cases with tumors in advanced stages should have elective postoperative therapy, such as chemotherapy and/or irradiation. Since recurrences (15%) of initially low-grade MALT lymphoma have been reported, these two cases should undergo periodic examination of the gastrointestinal tract at regular intervals over five years.