Lymphoplasmacytic lymphoma with IgG-κ paraproteinemia presenting as a hepatic bulky mass

Lymphoplasmacytic lymphoma (LPL) usually involves bone marrow (BM) and sometimes lymph nodes and spleen. LPL presenting as a hepatic mass lesion is extremely rare, with only one case reported in the English literature. A 70-year-old Japanese female presented to us with a right hypochondriac mass with tenderness. Computed tomography (CT) revealed a 14 cm-sized bulky hepatic mass. Laboratory findings showed a normal white blood cell count of 4.1×10⁹/L with 4% plasmacytoid lymphocytes; normocytic anemia, Hb 9.4 g/dL; high soluble IL-2 receptor level, 2,290 U/mL; and elevated IgG, 10,306 mg/dL. Furthermore, IgG-κ monoclonal protein was detected. ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT revealed abnormal uptake in the liver mass; left supraclavicular, parasternal, abdominal, and left inguinal lymph nodes; and bilateral lung bases. Magnetic resonance imaging showed no bone lesions. BM aspiration and liver biopsy showed predominant infiltration of small lymphocytes admixed with plasmacytoid lymphocytes and plasma cells. In the liver specimen, lymphoepithelial lesions were not observed. The small lymphocytes were positive for CD20, CD79a, and bcl-2, and negative for CD5, CD10, cyclin D1, and IRTA1; plasma cells in BM were positive for CD19, CD45, IgG, and κ-chain, and negative for CD20, and CD56. MYD88 L265P mutation, reported in approximately 40% of non-IgM LPL cases, was not detected in the liver specimen and BM cells. The frequency is lower than that of typical IgM LPL. These findings led us to a diagnosis of LPL with IgG-κ paraproteinemia. The patient underwent four courses of R-CHOP and two courses of Bendamustine-R. Partial remission was achieved.