Fig. 1From: Thrombotic thrombocytopenic purpura in a patient on long-term alpha-interferon therapy for essential thrombocythemia: a case reportCharacteristic histological findings in the renal biopsy. Periodic acid-methylamine silver staining shows a double-contour appearance of the basement membrane (red arrows) and an arteriole with luminal narrowing due to intimal edema and widening (yellow arrow)Back to article page