RESUMEN
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome in adults, which can be primary, or secondary to various causes. Unlike membranous nephropathy, FSGS is less likely to be associated with malignancy. Few cases have been reported of the occurrence of FSGS with hematological malignancies like multiple myeloma (MM). CASE REPORT A 48-year-old man presented with nephrotic syndrome and renal impairment and was diagnosed with primary FSGS after kidney biopsy, which showed a segmental scar with diffuse effacement of foot processes on electron microscopy. Treatment with steroids reduced proteinuria and stabilized the renal function. A few months later, the patient presented with acute Kidney Injury, bone pain, and anemia. A diagnosis of MM was made based on the bone marrow biopsy. Treatment of MM decreased proteinuria and improved renal function. CONCLUSIONS There is an association between FSGS and MM through an unclear mechanism.