Onion skin lesion in vessels is seen in

Malignant hypeension, defined as blood pressure usually greater than 200/120 mm Hg, and occurs in only about 5% of persons with elevated blood pressure.Mostly affected organ is kidney. The kidney may be essentially normal in size or slightlyshrunken, depending on the duration and severity of the hypeensive disease. Small, pinpoint petechial hemorrhages may appear on the coical surface from rupture of aerioles or glomerular capillaries, giving the kidney a peculiar, flea-bitten appearance.The microscopic changes reflect the pathogenetic events described earlier. Damage to the small vessels is manifestedas fibrinoid necrosis of the aerioles. The vessel walls show a homogeneous, granular eosinophilicappearance masking underlying detail. In the interlobular aeries and larger aerioles, proliferation of intimal cells after acute injury produces an onion-skin appearance.(Robbins basic pathology,9th edition.pg no.539)