Adrenal Gland - Angiectasis

Angiectasis (Figure 1 and Figure 2) in the adrenal cortex and medulla of rats and mice is characterized by focal to diffuse dilation of blood vessels (capillaries and/or veins). The dilated vessels are loosely to irregularly arranged and do not form discrete masses. They are lined by single layers of well-differentiated endothelial cells supported by a delicate fibrous stroma and contain variable amounts of blood.

Angiectasis can be associated with or secondary to other adrenal lesions such as inflammation, atrophy, degeneration, and neoplasia. It can also occur as a spontaneous age-related change in old rats and mice.

Angiectasis and hemangioma can be difficult to differentiate, but a distinction should be attempted. Hemangiomas tend to be well-circumscribed, unencapsulated masses composed of densely packed, dilated vascular spaces. The vascular spaces are lined by a single layer of normal-appearing endothelial cells aligned on usually delicate collagenous septa, though some cases exhibit more abundant collagenous stroma. In contrast, although angiectasis is also characterized by dilated vascular channels lined by unremarkable endothelium, the vascular channels are more loosely or irregularly arranged rather than presenting as a well-demarcated mass.