Waldenström's Macroglobulinemia/Lymphoplasmacytic Lymphoma Developing Renal AA Amyloidosis: A Case Report and Literature Review

AA amyloidosis is a rare renal complication of Waldenström's macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL). A 66-year-old man with WM/LPL presented with nephrotic syndrome. A renal biopsy showed AA amyloidosis. Chemotherapy resulted in the remission of hematologic and nephrotic syndromes. Two years into follow-up, he became infected with COVID-19 and had massive proteinuria, despite no relapse of WM/LPL. A second renal biopsy confirmed a diagnosis of AA amyloidosis. However, increased prednisolone did not improve proteinuria. The patient ultimately died of cryptococcal meningitis. This case highlights the diverse spectrum of renal involvement in monoclonal IgM-secreting diseases and difficulty in managing fatal complications.