Lymphomatous Interstitial Nephritis Coexistent with Paraneoplastic Crescentic Membranoproliferative Glomerulonephritis in a Case of Mantle Cell Lymphoma.

Mantle cell lymphoma (MCL) is a rare aggressive lymphoproliferative disorders (LPD) of B-cell lymphoma, which usually presents in advanced stages at initial diagnosis. Renal involvement in MCL is very rare, especially the combined presence of both glomerular and interstitial disease. We report on a patient with lymphomatous interstitial nephritis (LIN) coexistent with paraneoplastic crescentic membranoproliferative glomerulonephritis (MPGN), subsequently diagnosed to have disseminated MCL with bone marrow and lymph nodal infiltration. He was treated with rituximab-based chemotherapy and went into complete renal remission at 6-months of follow up.