Focal Segmental Glomerulosclerosis in a Patient Associated with Kappa-Light Chain Disease

Focal segmental glomerulosclerosis is a non-inflammatory glomerulopathy associated with nephrotic syndrome and end-stage renal failure. Focal segmental glomerulosclerosis related to plasma cell disorder is not common. A 46-year-old man presented to our outpatient clinic with lumbar pain that had been present for two years. He had been taking non-steroid anti-inflammatory drugs for two years because of his pain. He had no history of any systemic disease. Physical examination revealed a body mass index of 20 kg/m2 , blood pressure of 150/90 mmHg, 2+ bilateral lower extremity pitting edema and lumbar vertebrae sensitivity. We described a patient found to have nephrotic syndrome on the first medical examination, and lytic bone lesion and monoclonal gammopathy of the kappa light-chain type later on. A renal biopsy was performed and the histopathological findings were consisted with FSGS. Monoclonal gammopathy should be considered as the underlying disease in any patient diagnosed with focal segmental glomerulosclerosis.