The diagnosis of Bonnet-Dechaume-Blanc or Wyburn-Mason syndrome encompasses a spectrum of phenotypic expression. Features of the syndrome as originally described, and common to all, include arteriovenous malformations of the brain and orbit (with retinal and/or retrobulbar lesions). A portion of these patients manifest the complete expression of the disease with additional high-flow arteriovenous malformations of the maxillofacial or mandibular regions. These present the distinct and additional risks of life-threatening epistaxis or gingival haemorrhage. We suggest new diagnostic criteria for the syndrome. Applying insights from modern developmental biology to our series of 15 patients (the largest to date), together with a review of the literature, we have recognised metameric patterns of involvement in what we believe to be a disease of the neural crest or adjacent cephalic mesoderm. This allows us to propose a new rational classification reflecting the putative, underlying disorder and to suggest a new name: Cerebrofacial Arteriovenous Metameric Syndrome (CAMS).

We reviewed the angiographic study and clinical charts of 398 consecutive cases of intracranial arterial aneurysms, involving adults and children in the last 11 years (1986–1997). Giant aneurysms, dissecting aneurysms, mycotic aneurysms, and fusiform aneurysm were excluded. From the 341 patients presenting so-called berry aneurysm disease, attention was paid to multiple aneurysm sub group. One hundred and thirteen cases were analysed and compared with a group of single AA (228 cases) from the same material. Three longitudinal embryological territories giving rise to cranial endothelial cells and media were used to regroup the aneurysm sites. Eighty four cases presented aneurysms in the rostral region (74%), 20 cases with aneurysms involving rostral and middle territories (18%), 1 case presented aneurysm involving the middle and caudal territories (0.9%), 5 cases had aneurysms in the rostral and caudal territories (4.4%) and three cases presented aneurysm involving rostral, medial and caudal territories at the same time (2.7%). No multiple group was located in the middle or caudal territories alone. When several arterial territories were concerned they were adjacent in 95.6% of cases. Multiple AA could therefore result from mesodermal/neural crest stem cell or focal endothelial cell defect within one or two (usually consecutive) embryonic segments. Mirror lesions would correspond to bilateral symmetrical impairment in the same territory or involvement of a group of cells with bilateral distribution. AA may result from a constitutional vasculopathy, later expressed with focal overproduction of the arterial wall without remodelling correction. Secondary mutations and triggers are likely to be needed to lead to such AA production.

Five hundred and eighty one cerebral aneurysms seen from 1986–1997 were reviewed. Fifty five basilar tip aneurysms were demonstrated. The analysis of the anatomic disposition of the distal basilar artery in 47 of them showed the prevalence of caudal fusion in 91% of cases. The fusion is either symmetrical or asymmetrical. The neck of the aneurysm is preferentially implanted on the caudal part of the fusion. Recognition of the distal basilar artery anatomy allows the origin and extent of the perforating branches territory arising from the P1 segment to be predicted in each type of basilar tip disposition. The caudal variant supplies a small ipsilateral territory, whereas the cranial one often provides a bilateral supply. In the cranial arrangement one can observe interpeduncular anastomoses between the perforators across the midline prior to penetrating the mesencephalo-diencephalic structures. The risks involved in the sacrifice of the P1 segment can then be anticipated.

The authors report a case of total persistence of the hyoïdo-stapedial artery (HSA) discovered fortuitously in an adult. The external carotid artery terminated as the superficial temporal, middle deep temporal and transverse facial arteries; the HSA arose from the intrapetrous internal carotid artery, coursed within the middle ear and the middle cranial fossa where it gave off the middle meningeal artery before leaving the skull via the foramen spinosum to become the maxillary artery.