Rupture of the thyrocervical trunk branch from the subclavian artery in a patient with neurofibromatosis: a case report.
BACKGROUND
Vascular involvement in neurofibromatosis type 1 (NF1) is well recognized; however, rupture of extracranial arteries rarely occurs. We present a case of NF1 with rupture of the thyrocervical trunk, which branched from the right subclavian artery. A 76-year-old woman who has numerous café-au-lait spots and soft tumors of the skin manifested a sudden swelling of her neck accompanied with increasing pain. Radiological examinations revealed bleeding from the artery.


METHODS
Histological and immunohistochemical examinations were carried out using tissues that contained the affected vessel.


RESULTS
Proliferation of spindle cells positive for S-100 protein was seen in the adventitia of the ruptured vessel. Intimal thickening by proliferation of fibromuscular cells was also evident with irregularity of the media.


CONCLUSIONS
These findings suggest that the artery was disrupted by NF in the vascular wall. It is considered that NF in the arterial wall causes dysplasia of the smooth muscle layer in the intima and media and leads to fragility of the vessel. Twelve cases, including the present case, with rupture of extracranial arteries in NF1 have been reported in the past 10 years; two thirds of these occurred in extravisceral sites in which there is a good deal of physical movement. This suggests that a physiological factor is one of the triggers for arterial rupture, which occurs under a background of vascular fragility in NF1.