CYTOGENETIC STUDY OF 2 CASES WITH LYMPHOMA OF MUCOSA-ASSOCIATED LYMPHOID-TISSUE

Cytogenetic studies have been reported in fewer than 20 patients with lymphoma of mucosa associated lymphoid tissue (MALT). Two patients wit h this disease at the Clinical Center, National Institutes of Health h ad numerical and structural chromosome abnormalities, including +12 in both cases. The clonal karyotypes observed were -49,XX,t(2;8)(q33;p23 ),+3,-10,del(10)(q23),+12,+18 [cp] and 47,X,-X,i(6p),+7,+inv(12)(p13q1 3). Review of cytogenetic studies from published data showed that all cases of MALT lymphoma reported to date also have both numerical and s tructural chromosome abnormalities, the most frequent being numerical involvement of chromosomes 3, 7, and 12. Identification of a clonal ab normality can help establish the diagnosis when differential diagnosis includes atypical hyperplasia. Although trisomy 12 has been associate d with a poor prognosis in B-cell chronic lymphocytic lymphoma (B-CLL) , both these patients with MALT lymphoma have had long survival: 8 and 11 years, respectively.