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.
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