A rare case of internal jugular vein aneurysmal degeneration in a type 1 neurofibromatosis complicated by potentially life-threatening thrombosis.

Type 1 neurofibromatosis (NF1) is an autosomal dominant disorder characterized by multiple forms of neural crest cell proliferation. Associated venous malformations are extremely rare. We present a case of a giant thrombosed internal jugular aneurysm with brachiocephalic vein thrombosis in an NF1 patient. Surgical correction required prophylactic left brachiocephalic vein ligation, aneurysm evacuation, and proximal jugular vein ligation. Extreme vein friability caused severe intraoperative bleeding. Vein wall histology confirmed neurofibromatosis infiltration. Jugular vein aneurysm and infiltration in NF1, although exceedingly rare, can pose a serious threat to the patient during surgical correction, with major vessel thrombosis enhancing morbidity and mortality.