<prompt> All are seen in malignant hypertension except -Fibrinoid necrosisHyaline arteriolosclerosisNecrotizing glomerulonephritisHyperplastic arteriolosclerosis  <response>: Malignant hypertension, defined as blood pressure usuallygreater than 200120 mm Hg, is far less common in theUnited States than so-called benign hypertension andoccurs in only about 5 of persons with elevated bloodpressure. It may arise de novo i.e., without preexistinghypertension, or it may appear suddenly in a person whohad mild hypertension.PathogenesisThe basis for this turn for the worse in hypertensive subjectsis unclear, but the following sequence is suggested: The initialevent seems to be some form of vascular damage to thekidneys. This most commonly results from long-standinghypertension, with eventual injury to the arteriolar walls. Theresult is increased permeability of the small vessels to fibrinogenand other plasma proteins, endothelial injury, and plateletdeposition. This leads to the appearance of fibrinoidnecrosis of arterioles and small arteries and intravascularthrombosis. Mitogenic factors from platelets e.g., plateletderivedgrowth factor and plasma cause intimal hyperplasiaof vessels, resulting in the hyperplastic arteriolosclerosistypical of organizing injury of malignant hypertension and ofmorphologically similar thrombotic microangiopathies seelater and further narrowing of the lumina. The kidneysbecome markedly ischemic. 