Hyperplasia of mantle/marginal zone B cells with clear cytoplasm in peripheral lymph nodes - A clinicopathologic study of 35 cases

We describe 35 peripheral lymph nodes classified as mantle cell/marginal zo ne B-cell hyperplasia with clear cells using morphologic and immunologic fi ndings. For the purpose of this study, we obtained clinical follow-lip info rmation and performed immunoglobulin gene rearrangement studies on paraffin sections by polymerase chain reaction. Architecturally, the nodes were sug gestive of a benign process: no pericapsular infiltration, sinuses readily identified, scattered reactive follicles present, and paracortical nodular hyperplasia present. No monocytoid B cells were present. Focally, small lym phoid cells with round nuclei and clear cytoplasm (clear cells)formed monom orphic nodular, inverse follicular and/or marginal zone patterns. Flow cyto metry and immunohistochemical analysis revealed neither light chain restric tion nor an aberrant B-cell phenotype. Immunoglobulin gene rearrangement st udies showed a clonal band in 1 of 26 cases in which DNA was amplified. To ascertain the clinical relevance of this positive case, follow-lip informat ion was obtained 30 months after the initial biopsy; the 83-year-old woman was alive without treatment but had splenomegaly and bone marrow involvemen t by marginal zone B-cell lymphoma. The morphologic and immunologic criteri a used for diagnosis of mantle cell/marginal zone B-cell hyperplasia with c lear cytoplasm are valid; however, to rule out the possibility of occult ly mphoma, immunoglobulin gene rearrangement studies and clinical follow-up ar e necessary.