RESUMEN
A 73-year-old man with systemic edema and oliguria, which appeared within several days, was referred to our hospital. Urinalysis showed massive proteinuria, and the blood examination results indicated nephrotic syndrome. Renal biopsy revealed the existence of focal segmental glomerulosclerosis (FSGS), and further investigation indicated that the microscopic features were consistent with the "cellular variant (CELL)" according to the Columbia Classification. After biopsy, 40 mg per day of oral prednisolone was administered daily. With steroid therapy, the abnormal values of the blood examination and urinalysis gradually reached normal, and complete remission was achieved on day 43 after initiating steroid administration. Microscopic investigation by follow-up renal re-biopsy revealed several sclerosing glomeruli; however, other intact glomeruli had no endothelial proliferation, which is a hallmark of CELL. The patient was discharged after biopsy and observed as an outpatient, with maintenance of clinical remission.