Paraneoplastic podocytopathy associated with a duodenal gastrointestinal stromal tumor: a rare cause of nephrotic syndrome
Bárbara Alves Passos, Ana C. Gomes, António P. Cabages, Ana O. Monteiro, Jorge AlmeidaAbstract
Background:
Paraneoplastic glomerulopathies are an infrequent cause of adult nephrotic syndrome. Gastrointestinal stromal tumors (GISTs) have only exceptionally been associated with glomerular disease, with podocytopathies rarer still.
Case Presentation:
A 62-year-old man presented with edema and foamy urine, nephrotic-range proteinuria (10.72 g/24 h), severe hypoalbuminemia (14.5 g/L), and preserved renal function; autoimmune and serologic workup was negative. Renal biopsy showed diffuse podocyte foot-process effacement without immune deposits, consistent with minimal change disease. Imaging and endoscopic ultrasound-guided fine-needle aspiration identified a 14-mm SDH-competent duodenal GIST. A paraneoplastic podocytopathy was considered most likely. Prednisolone 1 mg/kg/day was started as bridging therapy, achieving complete remission sustained after tapering, while the tumor awaits resection.
Conclusion:
Underlying malignancy, including rare tumors such as GIST, should be considered in adult-onset nephrotic syndrome with minimal change disease once conventional etiologies are excluded. Durable remission after tumor resection would confirm the paraneoplastic link.