A rare case of monoclonal immunoglobulin deposition disease identified on renal biopsy

Abstract

Monoclonal light chain immunoglobulin deposition disease (MIDD) is a rare disease disorders in which monoclonal light chains are deposited within the basement membranes of renal structures, including glomeruli, tubules and vessel walls.1 The vast majority of patients diagnosed with MIDD will have renal insufficiency (80%) and half of MIDD patients have myeloma.2 We present the case of a 52-year-old female with a subacute history of impaired renal function and recent creatinine of 220. A renal biopsy performed at Flinders Medical Centre showed 50% renal cortical scarring with prominent tubular atrophy and peritubular basement membrane thickening on light microscopy. Regions containing periglomerular eosinophilic material were seen that labelled with kappa, favouring periglomerular light chain deposition. Direct immunofluorescence revealed linear labelling with kappa along the tubular basement membranes and electron microscopy showed punctate electron-dense deposits in areas, including the glomeruli and tubular basement membranes. The combined light microscopy, immunofluorescence, and electron microscopy results confirmed the diagnosis of MIDD. A discussion of MIDD is presented.