Vascular Lesions

The different lesions presented in this chapter are classified according to their hemodynamic characteristics: “Excluded” lesions are the lymphangiomas. Lesions with a predominant venous component are the orbital varicose veins (varices). Vascular lesions with arterial flow include cavernous hemangiomas, with characteristic diagnostic signs in A- and B-modes: hyperreflective, attenuating, with a usually homogeneous structure, and no spontaneous flow on color Doppler imaging (CDI) but with capillary arterial micro flows after injection of ultrasound contrast medium, their differential diagnosis being represented by hemangiopericytomas (= solitary fibrous tumor), fibrous tumors, and tumors of nerve sheath origin (neurofibroma and schwannoma); infantile hemangiomas (capillary hemangioma), arteriovenous fistulas and malformations, intravascular papillary endothelial hyperplasia (vegetative hemangioendothelioma or Masson's tumor), and arterial aneurysms. Vascular pathologies of the cavernous sinus impacting the orbit include direct carotid-cavernous fistulas, cavernous sinus dural arteriovenous fistulas, and intracavernous carotid aneurysm. Finally, orbital hematomas are discussed: often secondary to trauma or to the rupture of a pre-existing lesion (varicose vein+++, meningioma, cavernous hemangioma, lymphangioma, etc.) but which can also be spontaneous.