MARGINAL ZONE B-CELL LYMPHOMAS OF DIFFERENT SITES SHARE SIMILAR CYTOGENETIC AND MORPHOLOGIC FEATURES

Clinical, histologic, cytogenetic, and molecular genetic data of 31 pa tients with extranodal, nodal, and splenic marginal zone B-cell lympho ma (MZBCL) are presented. Despite these variable clinical manifestatio ns, a similar spectrum of morphologic features as well as distinctive immunophenotypic findings were noted. In all cases, a monotypic B-cell proliferation consistently negative for CD5, CD10, and CD23 was found expanding the marginal zone of the B follicle with and without coloni zation of the follicle centers. Clonal chromosomal abnormalities were detected in 23 of the 31 patients. Recurrent aberrations included whol e or partial trisomy 3 (18 cases), trisomy 18 (9 cases), and structura l rearrangements of chromosome 1 with breakpoints in 1q21 (9 cases) or 1p34 (6 cases), all of which were seen in extranodal, nodal, as well as splenic MZBCL. Abnormalities of the additional chromosome 3, such a s +del(3)(p13), +i(3)(q10), or structural changes involving the distal part of the long arm, were evident in 9 of the 18 cases. All recurren t abnormalities were found in MZBCL more frequently than in other hist ologic entities of B-cell non-Hodgkin's lymphoma (B-NHL). None of the known lymphoma-associated chromosomal changes or rearrangements of the BCL1, BCL2 BCL3, BCL6, and CMYC genes were detected. We conclude that MZBCL represent a distinct entity of B-NHL with characteristic morpho logic and immunophenotypic features and particular chromosomal abnorma lities, and that a close histogenetic relationship between extranodal, nodal, and splenic MZBCL is likely, although the clinical presentatio n may vary. (C) 1996 by The American Society of Hematology.