Fluorescence Immunophenotypic and Interphase Cytogenetic Characterization of Nodal Lymphoplasmacytic Lymphoma

Abstract

Lymphoplasmacytic lymphoma (LPL) is a small B-cell lymphoma with plasmacytic differentiation that does not fulfill the criteria for any other small B-cell lymphoma. Cytogenetic characterization of nodal LPL is limited and the distinction from marginal zone lymphomas with plasmacytic differentiation can be problematic. Thus, 17 cases of lymph node-based LPL were studied with fluorescence immunophenotypic and interphase cytogenetics for the investigation of neoplasia (FICTION) using a CD79a antibody and probes to detect trisomies of chromosomes 3 (15 cases), 12 (16 cases), and 18 (17 cases); rearrangements (R) of IgH (10 cases), BCL6 (6 cases), PAX5 (7 cases), and MALT1 (16 cases); and deletion 6q21 (7 cases). Cases with IgH R were further studied with an IgH/BCL2 probe. In cases without FICTION studies, previously reported fluorescence in situ hybridization results for IgH, PAX5, and deletion 6q21 were available from prior studies. The histopathology, immunophenotype, and available clinical data were also reviewed. Three pathologic categories were recognized: 5 classic LPL, 5 vaguely nodular polymorphous (VN-P), and 7 other. Among the classic LPL, 4/4 had an IgM paraproteinemia, 5/5 had bone marrow involvement (BM+), and 1/5 had +MALT1. One of one VN-P LPL had an IgM paraprotein, 2/4 were IgM+, 2/4 IgG+, 1/3 had BM+, and 1/5 had an IgH R. Among the other cases, 2/3 had a paraprotein, 2/7 were IgM+, 5/7 IgG+, and 0/3 had BM+. Of these cases, 1 showed +12, 1 +18, and 1 IgH/BCL2 rearrangement plus +18. None of the 17 cases had a 6q21 deletion or +3. Therefore, with rare exception, lymph node-based LPL with classic or more varied histopathologic features does not have the cytogenetic abnormalities frequently associated with bone marrow-based LPL/Waldenstrom macroglobulinemia or many of the marginal zone lymphomas. The search for better objective inclusionary criteria for LPL must continue.

An uncommon case of lymphoplasmacytic lymphoma in cerebellopontine angle region

“…However, deletions of 6q21 have been identified as a common site of chromosome loss in patients with WM. [11] These findings suggest that MYD88 mutations that lead to the activation of NF-kB family transcription factors are pivotal role in the pathogenesis of LPL. [2,12] Chronic infection with HIV and hepatitis C virus (HCV) has also been implicated as risk factors.…”

Gamma Heavy-chain Disease

“…19,27 The detailed morphologic features of nodal LPL have been previously investigated. 3,5,26,27 The most characteristic nodal pattern of LPL consists of a partially preserved architecture with patent sinuses and an expansion by small lymphocytes and plasma cells, wherein plasma cells usually represent a minority of the cellularity. Cases with this pattern are highly associated with bone marrow involvement and an IgM paraprotein.…”

Waldenström Macroglobulinemia

“…3,5,11,[42][43][44] In the classical picture, lymphoma subtotally involves lymph node in a diffuse pattern, preferentially involving the interfollicular regions, medulla, and hilum with relative sparing of the sinuses and superficial cortex (Figs. 3,5,11,[42][43][44] In the classical picture, lymphoma subtotally involves lymph node in a diffuse pattern, preferentially involving the interfollicular regions, medulla, and hilum with relative sparing of the sinuses and superficial cortex (Figs.…”

“…11,42 Lymphocytes or plasma cells can be minimal or abundant, and therefore, as in the bone marrow, WM in lymph nodes can be divided into lymphoplasmacytoid (Fig. 11,42 Lymphocytes or plasma cells can be minimal or abundant, and therefore, as in the bone marrow, WM in lymph nodes can be divided into lymphoplasmacytoid (Fig.…”