[Transient ischaemic attacks due to hypoplasia of the internal carotid artery in a patient with congenital Horner's syndrome].

INTRODUCTION

Hypoplasia of the internal carotid artery (ICA) is a rare developmental anomaly sometime revealed by transient ischaemic attaks (TIA). Association with a Horner's syndrome is very rare.

CASE REPORT

We report the case of a 42-year-old woman who presented with a TIA and a cervical murmur. Horner's syndrome with iris hypopigmentation was present shortly after birth. Magnetic resonance imaging showed no dissection but hypoplasia of the ICA. Blood flow in the ICA was antegrade through several branches constituting a rete mirabile across the carotid canal, and via collateral arteries from ipsilateral external carotid artery.

CONCLUSION

Horner's syndrome in the setting of TIA evokes a carotid dissection. A skull base CT scan demonstrating carotid canal hypoplasia can rule out an ICA dissection and allows diagnosis of a congenital arterial anomaly.