Neurofibromatosis type 1 (NF-1) is a genetic disorder that affects one in 3000 individuals. Although NF-1 notably involves nerves and connective tissue, vascular involvement in large series is estimated to range from 0.4% to 6.4%. Jugular vein involvement in these patients is rare. Spontaneous neck hematomas and hemorrhages are also unusual. We present a case of a NF-1 patient with a spontaneous neck hematoma with possible leakage from the left internal jugular vein, presenting as a lateral neck mass. The fragility of the vein wall and the surrounding tissue led patient to a severe intraoperative bleeding. Pathological examination revealed degenerated neurofibroma which was in contact with or infiltrated the vein wall. ENT and other clinicians should be aware of this potentially fatal entity considering that it may present as a lateral neck mass.