Tooth - Angiectasis
The difference between angiectasis and hemangioma can be unclear. Hemangiomas tend to be well-circumscribed unencapsulated masses composed of tightly packed dilated vascular spaces. Each vascular space is enclosed and lined by a single layer of normal-appearing endothelial cells aligned on collagenous septa, which are usually thin, although some have broad collagenous stroma. Angiectasis does not usually present as a well-circumscribed mass, as the dilated vascular channels often course irregularly through connective tissue.
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Long PH, Leininger JR. 1999. Teeth. In: Pathology of the Mouse (Maronpot RR, ed). Cache River Press, St Louis, MO, 13-28.Abstract: http://www.cacheriverpress.com/books/pathmouse.htm