血管扩张Angiectasis · 骨骼肌 · 骨骼肌肉系统 · NTP ntp-0595

Comment：
Angiectasis is a nonproliferative lesion in which preexisting vascular spaces are dilated and prominent ( Figure 1 and Figure 2 ). The vessels are lined by a single layer of flat endothelium in which the endothelial cells are normal in appearance, number, and size. Angiectasis is typically an incidental lesion, and its etiology and pathogenesis are often obscure. It is important to distinguish angiectasis from a hemangioma. This can be difficult because the distinction is not always obvious and angiectatic lesions can appear in regions of hemangiomas. Hemangiomas tend to be well-circumscribed, unencapsulated masses composed of tightly packed, dilated vascular spaces that compress surrounding tissues. While the vascular spaces are lined by a single layer of well-differentiated endothelium, endothelial nuclei are typically increased in number and slightly enlarged. In general, the absence of endothelial cell proliferation and/or nuclear atypia differentiates angiectasis from a neoplastic vascular lesion. In addition, angiectasis does not typically present as a well-circumscribed mass; the dilated vascular channels often course irregularly through the tissue.

Recommendation：
When present, angiectasis should be diagnosed and assigned a severity grade.