RESUMO
BACKGROUND: Monoclonal immunoglobulin deposition disease (MIDD) is a rare disease, usually manifesting between the 5(th) and 6(th) decades of life but can also occur earlier. Characteristic feature of MIDD is a non-fibrillar, Congo red negative deposition of monoclonal immunoglobulins in various organs, including the kidneys. Depending on the composition of the deposits, MIDD is classified into 3 types; light chain deposition disease (LCDD), which is the most common form, heavy chain deposition disease (HCDD) and light and heavy chain deposition disease (LHCDD). Kidney involvement is common in MIDD. Renal biopsy reveals nodular sclerosing glomerulopathy on light microscopy and diffuse linear staining of glomerular and tubular basement membranes on immunofluorescence (IF) microscopy. CASE PRESENTATION: A 38-year-old male patient recently diagnosed with hypertension presented with lower extremity edema, shortness of breath, and fatigue. The workup that was performed in a different hospital prior to this admission, demonstrated the presence of significant proteinuria and renal failure. He was intermittently dialyzed and a renal biopsy was obtained, which showed LCDD. Further laboratory workup revealed an increase of IgM, kappa chain and ß2 microglobulin chain, in addition to proteinuria and renal insufficiency. Bone marrow biopsy demonstrated an involvement of 30% with plasma cells. The flow cytometry test showed monotypic plasma cells expressing intracytoplasmic kappa light chain restriction with kappa to lambda ratio of 35/1. The diagnosis of LCDD was established. Treatment with steroids and bortezomib was initiated. CONCLUSIONS: MIDD is an unusual disease and LCDD is the most common form of MIDD. The peak incidence is around the 5(th) and 6(th) decade of life, however, LCDD can also be found in younger patients. Renal involvement, proteinuria, hematuria, and hypertension are markers of the initial clinical presentation. Nodular sclerosing glomerulopathy is found in about 60% of the affected patients. Early diagnosis and early treatment improve the prognostic course of LCDD.
