Renal Biopsy as a Diagnostic Salvage Modality in Gouty Nephropathy Coexisting With Amyloid A Amyloidosis.

Gouty nephropathy is an uncommon renal complication arising from chronic hyperuricemia, and its coexistence with Amyloid A (AA) (secondary) amyloidosis is exceedingly rare. We describe a 60-year-old man with a long-standing history of untreated polyarticular gout who presented with progressive joint pain, nephrotic-range proteinuria, and renal impairment. Laboratory evaluation showed elevated serum uric acid levels and impaired renal function. Renal biopsy revealed urate crystal deposits (tophi) with associated inflammatory changes consistent with gouty nephropathy, along with Congo red-positive amyloid deposits that were confirmed as AA amyloidosis by immunohistochemistry. This report highlights the critical diagnostic value of renal biopsy in identifying the rare coexistence of gouty nephropathy and AA amyloidosis within the same renal specimen. Recognizing this association is essential for prompt diagnosis and appropriate management, particularly in patients with gout who present with renal impairment and significant proteinuria.