Splenic Marginal Zone Lymphoma and Concurrent Membranoproliferative Glomerulonephritis With IgMKappa Deposits in a HCV-Seropositive Patient

We report a case of membranoproliferative glomerulonephritis (MPGN) with IgMκ light chain deposits in a patient with chronic hepatitis C infection and simultaneous onset of monoclonal IgMκ gammopathy with concurrent small B-cell lymphoproliferative disease. The patient presented with hepatosplenomegaly and a uremic state that necessitated dialysis without any clinical signs of systemic disease apart from the chronic infection with hepatitis C virus. The diagnostic approach led to a renal biopsy that revealed MPGN with dominant IgMκ deposits and interstitium infiltration by the lymphoid cells. The bone marrow biopsy findings were consistent with splenic marginal zone lymphoma, a rare lymphoproliferative disorder with a rare association with MPGN. Our case indicates high diagnostic value of renal biopsy for rare lymphoplasmacytic neoplasms with renal dysfunction as their predominant clinical manifestation.