Gastric Mucosa-Associated Lymphoid Tissue (MALT Lymphoma) and Immunoglobulin IgM Kappa Gammopathy: Is There an Association?: 927

Introduction: A 58-year-old man with no significant history presented with progressive dyspnea and weight loss over the past 6 months. He also complained of intermittent nose bleeds and diarrhea for 2 months. On physical exam he was febrile to 38.4 C, tachycardic, tachypneic, and had mild tenderness to palpation in the epigastric region. Significant laboratory work up revealed a normocytic hemoglobin of 11.5 gm/dL, total protein of 9.1, albumin of 2.7, and globulin of 6.4 gm/dL. Further work-up revealed paraprotenemia with elevated IgM levels to 5,880 mg/dL with normal IgA and IgG. Serum protein immunofixation revealed a monoclonal gammopathy of the IgM Kappa type at 895 mg/dl. Urine protein immunofixation found monoclonal-free kappa light chains. Computed tomography of the abdomen demonstrated marked thickening of the stomach with splenomegaly, left adrenal enlargement, and retroperitoneal adenopathy. The patient underwent an endoscopic evaluation and gastric biopsies which confirmed a small B cell lymphoma consistent with gastric MALT lymphoma. Cytogenetic analysis demonstrated a translocation (11:18), confirming the diagnosis. Interestingly, Helicobacter pylori stains were negative. A thorough literature review revealed several studies finding an association between monoclonal gammopathies and ‘extragastric’ MALT lymphoma. As such, up to one-third of patients with extragastric MALT lymphoma also have monoclonal gammopathy, though, IgM gammopathy is not exceedingly rare in extragastric MALT lymphoma, an elevated IgM level is extremely rare in gastric MALT lymphoma with only one Korean case report in the literature. The findings of monoclonal IgM Kappa gammopathy are most often associated with Waldenström’s macroglobulinemia (WM). It is important to distinguish the two as the treatment of WM differs greatly from the treatment of MALT lymphoma. Extensive literature review on this topic found that hypergammopathy is associated with a more difficult to treat extragastric MALT lymphoma as well as distant metastasis. Thus, it has been suggested that paraprotein analysis be done routinely in the staging of MALT lymphoma along with monitoring of IgM levels to monitor therapeutic response. It is not known if this therapeutic response can be found in gastric MALT lymphoma. Our patient will be followed with serial IgM levels to see if the same response to treatment occurs. We highlight in this case report the rare finding of IgM kappa gammopathy and gastric MALT lymphoma, which has not been extensively described in the literature.