Multiple organ mucosa-associated lymphoid tissue lymphomas often involve the intestine

BACKGROUND. Low grade mucose-associated lymphoid tissue (MALT) lymphomas us ually are confined to single extranodal organs. Although some case reports have been published, clinicopathologic characteristics of multiorgan MALT l ymphomas remain unclear. METHODS, The authors evaluated 7 MALT lymphoma cases involving multiorgans in the past 7 years. In this period, they experienced 304 cases of MALT lym phomas. They analyzed the clinicopathologic features of these cases, includ ing examination of clonal comparison among the lesions. RESULTS. The patients, 4 females and 3 males, were aged 55-68 years old (av erage, 60.1 years). Four cases showed multiple organ involvement at the ini tial diagnosis or after a short period. In the other three cases, primary f oci were the stomach, thyroid gland, and ocular adnexa; after a rather long period (3 years or more), distant metastases were found. Although intestin al primary lymphomas are rather rare, six of the seven cases showed large i ntestinal involvement. Lymph node involvement was proven in only three case s. The patients were rather resistant to the various therapeutic approaches . Although six patients are alive, five are with disease. DNA analyses reve aled that in five of the cases evaluated, identical clones were detected am ong the different affected organs. CONCLUSIONS. Multiorgan MALT lymphomas are rather rare. Most cases probably derived from a single clone, and lymphoma cells may selectively move among MALTs via a homing system with preferential involvement of the colon. Beca use multiorgan MALT lymphomas rarely achieve complete remission by treatmen t with combination chemotherapy or irradiation, MALT lymphomatous lesions s hould be checked carefully, especially in the large intestine. (C) 2001 Ame rican Cancer Society.