AA Renal amyloidosis associated with a gastrointestinal stromal tumor

AA amyloidosis is an uncommon complication of solid malignancies and is usually associated with chronic inflammatory conditions. Its association with gastrointestinal stromal tumors (GISTs) is exceptionally rare, with only a few cases reported in the literature.

We describe a 64-year-old woman with metastatic duodenal GIST and peritoneal carcinomatosis. Four months after diagnosis, she developed severe nephrotic syndrome, acute kidney injury, and rapidly progressive renal failure requiring hemodialysis. Kidney biopsy revealed glomerular and vascular AA amyloid deposits confirmed by Congo red staining and immunohistochemistry for serum amyloid A protein, together with acute tubular necrosis. Extensive evaluation excluded other causes of secondary amyloidosis. Despite treatment with imatinib and evidence of limited radiological tumor response, renal function did not recover and the patient ultimately died from infectious and hemorrhagic complications.

GIST-associated AA amyloidosis is an extremely rare entity. Reported cases share the presence of large tumors with necrotic areas and marked systemic inflammation, supporting a role for sustained serum amyloid A overproduction in amyloid deposition. Renal involvement is often severe and frequently progresses to kidney replacement therapy.

GIST should be considered a potential cause of AA amyloidosis in patients presenting with nephrotic syndrome or kidney dysfunction in the setting of a solid tumor with high tumor burden and persistent systemic inflammation. Early recognition of this association may facilitate diagnosis and management of a potentially devastating complication.