Wyburn-Mason or Bonnet-Dechaume-Blanc as Cerebrofacial Arteriovenous Metameric Syndromes (CAMS). A New Concept and a New Classification

Abstract

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 lifethreatening 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).

Figure 1

Schematic drawing showing potential zones of involvement. I: facial; II: orbital; III: cerebral. Locations of lesions within zones: 1) cutaneous; 2) maxillofacial; 3) retina; 4) optic nerve; 5) hypothalamus/chiasm/hypophysis; 6) thalamus; 7) occipital lobe; 8) midbrain; 9) cerebellum.

Figure 2

A) Clinical photograph demonstrates midline angioma of the nose. B) Right ICA angiogram demonstrates hypothalamic AVM. No orbital involvement is seen. C) Facial artery angiogram demonstrates the high-flow nasal AVM.

Figure 3

A, B) MRI Brain. A) Sagittal T1 shows large AVM nidus in thalamus and hypothalamus with sparing of the midbrain. B) Axial T2 shows unilateral nidus centred on the deep grey-matter structures. Note also cerebromalacia at left occipital pole (arrow). C) Left ICA angiogram (lat) shows full extent of nidus. Note extension along optic nerve (arrow) and choroidal blush (arrowhead). D) Left external carotid angiogram (lat) shows maxillofacial component of vascular lesion. E) CT of the head on bone windows. Note the hypoplasia of the left maxillofacial skeleton.

Figure 4

A) Clinical photograph of vascular lesion of the nose. B, C) MRI brain: B) Left parasagittal T1 shows hypothalamic involvement with several flow voids also visible in the thalamus. C) Axial T2 showing midline hypothalamic location of the nidus. Note extension into the left orbit around optic nerve. D, E) Left ICA angiogram (lateral, D and AP, E) shows the elongated nidus. Note the midline location and the partly separate thalamic component. F, G) Left ECA angiogram shows maxillofacial component of the lesion. Note maxillary and nasal AVMs, and aneurysms of the maxillary artery in (F) and maxillary and facial arteries in (G).

Figure 4

A) Clinical photograph of vascular lesion of the nose. B, C) MRI brain: B) Left parasagittal T1 shows hypothalamic involvement with several flow voids also visible in the thalamus. C) Axial T2 showing midline hypothalamic location of the nidus. Note extension into the left orbit around optic nerve. D, E) Left ICA angiogram (lateral, D and AP, E) shows the elongated nidus. Note the midline location and the partly separate thalamic component. F, G) Left ECA angiogram shows maxillofacial component of the lesion. Note maxillary and nasal AVMs, and aneurysms of the maxillary artery in (F) and maxillary and facial arteries in (G).

Figure 5

A) Drawing of the rostrum of an embryo, the arrows indicate progressive closure of the neural folds and curling inferiorly to the anterior lip of the neuropore. Stippled area indicates anlage of the hypothalamus, adenohypophysis and covering nasal tissues. B, C) Oblique and frontal views showing migration of this region. D) Later embryo showing nasal tissues in their final location. Future hypothalamus and adenohypophysis are still just visible prior to closure of the maxillary buds.

Figure 6

Case reported by Tʼneron et Al showing (A) brain AVM involving the thalamus and optic nerve, (B) mandible and (C) cerebellum. We classify this lesion complex as CAMS 3. Reproduced with permission.

Figure 7

Schematic drawing of the proposed metameric disease groups (CAMS 1-3), illustrating their main areas of involvement. Note also from the drawing that the upper cervical Cobb syndrome may simply represent the caudal extension of the same disease spectrum: SAMS (Spinal Arteriovenous Metameric Syndrome) 1.