An Unusual Case of Lymphoplasmacytic Lymphoma/waldenström Macroglobulinemia Presenting with Intractable Seizures and Interference with Automated Testing

Lymphoplasmacytic lymphoma (LPL) is a B cell neoplasm composed of small lymphocytes, plasmacytoid lymphocytes, and plasma cells, which typically involves the bone marrow. Most cases of LPL present with Waldenstrom macroglobulinemia (WM) defined as the presence of monoclonal immunoglobulins of IgM type and LPL in the bone marrow. Herein, we present a case of LPL/WM presenting with intractable refractory seizures. A 71-year-old man with a 5-month history of seizures was brought to the emergency room after being found unresponsive. Automated hematology analysis revealed imprecise counts, wide variation, and multiple error flags. Peripheral smear review showed extracellular pale blue clumps of amorphous material. A marked cryoprecipitate of 7% was detected on a cryoglobulin screen. Serum protein electrophoresis (SPEP) detected a M-protein (1.58 g/dL) in the gamma region. Serum immunofixation revealed an IgM lambda monoclonal protein. A bone marrow biopsy showed hypercellularity with increased lymphocytes forming interstitial aggregates, admixed with plasmacytoid lymphocytes and plasma cells. Immunohistochemically, the lymphoma cells were positive for CD20 and negative for CD3, CD5, CD10, CD23, Cyclin D1 (Bcl-1), and Bcl-6. CD138 highlighted increased plasma cells. Flow cytometric analysis revealed 2.7% B cells with a predominance of lambda light chains, suggestive of a monoclonal B cell population. MYD88 mutational analysis revealed c.794T>C(p.L265P) mutation. A diagnosis of lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia was established. The patient underwent plasmapheresis leading to significant improvement in his symptoms. This case highlights a rare, unusual presentation of LPL/WM where the interference in automated testing led to identification of cryoglobulinemia and subsequent diagnosis of LPL/WM.