It may mimic an angiosarcoma, with lesions that are red or purplish 5-mm to 5-cm papules and deep nodules on the head, neck, or upper extremities.

Intravascular papillary endothelial hyperplasia typically manifest as deep nodules or well-defined, round, red, or purple superficial papules.

[6][7] Although there are numerous possibilities, the pathophysiology and causation of intravascular papillary endothelial hyperplasia remain unknown.

IPEH is made up of an intravascular proliferation of many papillae with an endothelial surface and a connective tissue core.

[11] It differs from other neoplastic lesions in that it is often encapsulated or well-circumscribed, displaying distinctive papillary fronds, and the vascular wall completely restricts the proliferative process.

[3] The most prevalent variety, known as the primary or pure form, develops in subcutaneous soft tissue and usually arises in a dilated channel, most commonly a vein rather than an artery.