Hyperplastic aeriolitis is seen in

Malignant hypeension, defined as blood pressure usuallygreater than 200/120 mm Hg, andoccurs in only about 5% of persons with elevated blood pressure.The basis for this turn for the worse in hypeensive 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-standinghypeension, with eventual injury to the aeriolar 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 aerioles and small aeries and intravascularthrombosis. Mitogenic factors from platelets (e.g., plateletderivedgrowth factor) and plasma cause intimal hyperplasiaof vessels, resulting in the hyperplastic aeriolosclerosistypical of organizing injury of malignant hypeension and ofmorphologically similar thrombotic microangiopathies (seelater) and fuher narrowing of the lumina.Robbins Basic pathology,9th edition,pg no.539