Secondary amyloidosis associated with tuberculosis in renal biopsy

Abstract

A 46-year-old woman presented with a 4-month history of edema, fever and cough [Brazil; date not given]. Her chest x-ray showed an opacification in the upper lobe of the left lung, but laboratory tests were all negative for tuberculosis (TB) infection. Nevertheless, treatment for PTB was started. Serum creatinine and albumin levels were 0.8 mg/dl and 2.5 g/dl, respectively, and urinary protein excretion was 7.5 g/24 h. A renal biopsy performed after six weeks of anti-TB therapy showed a mild mesangial expansion of amorphous and acellular pale eosinophilic material suggestive of amyloid. The interstitial area showed foci of mixed inflammatory cell infiltrate and epithelioid granulomas with Langhans giant cells and central necrosis. Her final diagnosis was secondary amyloidosis and granulomatous interstitial nephritis compatible with tuberculosis. Two years later, her albumin level was 4.2 g/24 h, serum creatinine was 1.0 mg/dl, proteinuria decreased to 1.2 g/24 h, and all her symptoms disappeared.