[Spontaneous dissection of the internal carotid artery: apropos of a case].

Dissections of the extracranial internal carotid artery are probably underestimated in the general population. They are often unrecognized and asymptomatic as shown in this case report and are only the cause of 1 to 4% of cerebral ischaemic accidents. However, they are responsible for 5 to 20% of such accidents in adults younger than 30 years of age. The nontraumatic nature of the carotid artery dissection in our case has been suggested by the medical history although minor trauma could have been missed. A skin biopsy has enabled us to eliminate elastopathies such as Marfan's or Ehlers-Danlos' syndrome. The diagnosis of dissection has been suggested by a Doppler colour echography ; it was confirmed by the arteriography which revealed a long dissection looking like "string sign" at the level of the internal carotid artery just over the carotid bulb. As far as the evolution is concerned, a medical treatment made it quickly favourable.