||An arteriovenous malformation may occasionally involve the blood vessels within the pinna. Clinically, engorged vessels will distort the normal architecture of the pinna and palpation of the involved area will reveal pulsations. A loud bruit can also be heard over the involved area.
A large arteriovenous malformation may shunt a significant amount of the cardiac output. Since the pinna is in such an exposed location and the skin is thin, slight trauma or infection may rupture the vessels contained within the malformation, producing a dramatic hemorrhage.
This patient has a large arteriovenous malformation involving the entire pinna. The skin shows numerous dilated subcutaneous vessels and the entire pinna has a dusky red discoloration.