Lupus podocytopathy as a first renal manifestation in long-standing systemic lupus erythematosus: a case report.

Lupus podocytopathy (LP) is an increasingly recognised and histopathologically distinct entity within the spectrum of lupus nephritis (LN). It is defined by diffuse podocyte foot process effacement in the absence of subendothelial or subepithelial immune complex deposition and often mimics minimal change disease or focal segmental glomerulosclerosis. LP is typically observed at the onset of systemic lupus erythematosus (SLE) or in patients with known LN. We report a rare case of LP in a 28-year-old Japanese woman with a 12-year history of SLE and no prior renal involvement. She presented with fever, malar rash, arthralgia, and progressive bilateral lower extremity oedema. Laboratory studies revealed marked hypoalbuminemia (1.5 g/dl), nephrotic-range proteinuria (15 g/gCr), elevated anti-dsDNA antibody titers (>400 IU/ml), and hypocomplementemia. Renal biopsy revealed ISN/RPS 2018 class II LN, with mild mesangial hypercellularity and mesangial deposition of IgG, C3, and C1q, without subendothelial or subepithelial immune complexes. Electron microscopy confirmed extensive foot process effacement, establishing the diagnosis of LP. The coexistence of class II LN and LP accounted for the acute onset of nephrotic syndrome in the absence of proliferative changes. The patient was treated with methylprednisolone pulse therapy, high-dose corticosteroids, and intravenous cyclophosphamide, followed by oral cyclosporine. This regimen resulted in prompt clinical and immunological improvement, including near-complete resolution of proteinuria. She remained in remission throughout a 6-month follow-up. This case emphasises the need to consider LP in SLE patients with nephrotic syndrome, even in the absence of prior renal complications during long-term follow-up.