Cross section of an aeriole shows 'onion skin thickening' of its wall. It is seen in:

Hyperplastic aeriolosclerosis: Associated with malignant hypeension. It is a concentric, cellular thickening (i.e., onion-skinning) of the wall associated with fibrinoid necrosis.Atherosclerosis: Grossly recognizable atherosclerosis begins as a fatty streak and progresses to a fibroatheroma. Monckeberg medial calcification: A condition of little clinical significance because the changes are nonstenotic. It is characterized by medial calcification ("pipestem rigidity") of the muscular aeries (often radial and ulnar aeries) in elderly men. Hyaline aeriolosclerosis: Associated with benign hypeension. It is eosinophilic, acellular thickening of the wall of aerioles. Ref: Wyatt C., Kemp W.L., Moos P.J., Burns D.K., Brown T.G. (2008). Chapter 9. Vascular Pathology. In C. Wyatt, W.L. Kemp, P.J. Moos, D.K. Burns, T.G. Brown (Eds), Pathology: The Big Picture.