When Waldenström macroglobulinemia hits the kidney: Description of a case series and management of a “rare in rare” scenario

Background: Renal injury related to Waldenström macroglobulinemia (WM) occurs in approximately 3% of patients. Kidney biopsy is crucial to discriminate between distinct histopathological entities such as glomerular (amyloidotic and non-amyloidotic), tubulo-interstitial and non-paraprotein mediated renal damage. In this context, disease characterization, management, relationship between renal, and hematological response have been poorly explored. We collected clinical, genetic and laboratory data of seven cases of biopsy-proven renal involvement by WM managed at our academic center and focused on three cases we judged paradigmatic discussing their histopathological patterns, clinical features, and therapeutic options. Case: In this illustrative case series, we confirm that serum creatinine levels and 24 h proteinuria are parameters that when altered should prompt the clinical suspicion of WM-related renal involvement, even if at present there are not precise cut-off levels recommending ...