A Case of a Lymphoplasmacytic Lymphoma with Trisomy 12 in the Lymphoid Population and Deletion 13q in the Unstimulated Cell Culture.

OBJECTIVES: Lymphoplasmacytic lymphoma (LPL, previously termed lymphoplasmacytoid lymphoma) is an uncommon mature B-cell lymphoma usually involving the bone marrow and less commonly the spleen and/or lymph nodes. The majority of patients with LPL have a circulating monoclonal immunoglobulin M (IgM) that can lead to a hyperviscosity syndrome known as Waldenstrom macroglobulinemia (WM). Although LPL appears to be a sporadic disease in the majority of cases, a familial predisposition is present in some cases. The main chromosomal abnormalities are trisomy 12, trisomy 3, isochromosome 6p, and 14q rearrangements involving IgH among complex karyotypes. Herein, we present an 89-year-old male patient who presents with LPL involving 80% of the marrow cellularity with circulating lymphoma cells. Chromosomal analysis detected two unrelated abnormal clonal populations: one clone has trisomy 12 as the sole abnormality in the stimulated culture, while the other clone has a 13q deletion as the sole abnormality in the cells from the non-stimulated culture. Trisomy 12 is one of the most common abnormalities in B-CLL and it is associated with an intermediate prognosis. Deletions 13q have been identified in B-cell malignancies, non-Hodgkin's lymphomas (NHL), as well as myelodysplastic syndromes and chronic myeloproliferative neoplasms (Heim and Mitelman, 2015). Trisomy 12/13q- FISH slide was reviewed looking at the segmented cells. Fifty segmented cells were scored and a 13q- pattern was detected in 36% (18/50) of the cells suggesting that this finding (the 13q- clone) may be myeloid in origin. Clinicopathologic correlation of these results was recommended.