An unusual case of glomerulonephritis in a patient with non-Hodgkin Mucosal Associated Lymphoid Tissue (MALT) B-cell lymphoma

BACKGROUND: Kidney involvement in non-Hodgkin lymphoma is well recognized and glomerulonephritis, when present, has been commonly reported to be associated with a membranoproliferative pattern. CASE PRESENTATION: We report a case of a 58-year-old lady with a recurrence of non-Hodgkin MALT B-cell lymphoma, presenting with acute kidney injury, nephrotic range proteinuria and a cellular urinalysis. She underwent a renal biopsy that showed a severe diffuse proliferative and exudative lupus-like glomerulonephritis, which is likely paraneoplastic in nature. We discuss the differential diagnosis and possible pathogenesis of glomerular injury in lymphoma-related proliferative glomerulonephritis. CONCLUSION: Differentiating between true lupus nephritis and a paraneoplastic glomerulonephritis is important, as it would have significant implications on treatment and clinical course.