Abstract

CUNHA, Ivo; SILVA, Sandra; HENRIQUE, Rui  and  COSTA, Maximino. Light chain deposition disease: atypical associations in a rare disease. Port J Nephrol Hypert [online]. 2018, vol.32, n.3, pp.289-292. ISSN 0872-0169.

Light chain deposition disease is a systemic disorder characterized by deposition of monoclonal light chains in various organs. We present a case of a 58#8209;year#8209;old woman who was referred for a nephrology consultation due to worsening renal function and nephrotic range proteinuria. The diagnosis work#8209;up mentioned a plasmatic creatinine of 1.5mg/dL (estimated glomerular filtration rate of 38 mL/min/1.73m2 by MDRD equation), a urinary sediment with microhematuria, a protein/creatinine ratio of 5, a seric and urinary immunoelectrophoresis compatible with a monoclonal gammopathy IgG/Kappa, hypocomplementemia, type II cryoglobulinemia and a pulmonary nodule of irregular shape 15mm in diameter. A renal biopsy was performed and showed a marked expansion of the mesangium with nodules of amorphous material and small outbreaks of tubular atrophy associated with interstitial fibrosis. The nodules were PAS positive and Congo red negative and stained for light chain kappa by immunocytochemistry. Immunofluorescence was negative for IgA, IgG, IgM, C1q and C3c. A diagnosis of light chain deposition disease was made and concomitant multiple myeloma excluded. Treatment was initiated with bortezomib, dexamethasone and thalidomide with complete hematological remission and improvement in renal function. She also showed normalization of the cryoglobulinemia and disappearance of the pulmonary nodule previously detected, despite worsening of cardiac function as a result of the chemotherapy implemented. This clinical case highlights the well-known renal involvement in light chain deposition disease, but also some atypical clinical associations, namely type II cryoglobulinemia and pulmonary nodule disease.

Keywords : Cryoglobulinemia; light chain deposition disease; monoclonal immunoglobulin deposition disease; pulmonary nodule.

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