<prompt> Postmoem studies of a man shows onion skin thickening of aeriolar wall which is characteristic of:AtherosclerosisMedial calcific sclerosisHyaline aeriosclerosisHyperplastic aeriosclerosis  <response>: Hyperplastic aeriosclerosis occurs in severe malignant hypeension; vessels exhibit onion-skin lesions, characterized by concentric, laminated thickening of the walls and luminal narrowing. The laminations consist of smooth muscle cells with thickened, reduplicated basement membranes; in malignant hypeension they are accompanied by fibrinoid deposits and vessel wall necrosis necrotizing aeriolitis, paicularly in kidney. Ref: Robbins Cotran Pathologic Basis of Disease, By Vinay Kumar, Abul K. Abbas, Nelson Fausto, Jon C. Aster, 2009, Chapter 11. 