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The triad of concomitant retinal or orbital arteriovenous malformations (AVM), intracranial AVM, and vascular facial naevi were described in the 1940s and comprise a rare phacomatoses known as Wyburn-Mason syndrome. We present a variant of this syndrome with an association not, to our knowledge, previously reported in the literature, and discuss radiological findings, management, and therapeutic options.
An asymptomatic 14 year old girl was referred following a routine optometry visit. She had been a patient at Great Ormond Street Hospital, London, with a large left cavernous facial haemangioma and had undergone several sclerotherapy injections in the past. Neurologically, there was no history of epilepsy, or evidence of midbrain or cerebellar dysfunction. Ophthalmic examination revealed visual acuities of 6/5 bilaterally with normal intraocular pressures. Colour vision was normal on Ishihara pseudo-isochromatic plates and there were no deficits detected by a Humphrey field analyser 24-2 threshold test. Fundus examination showed markedly convoluted and enlarged retinal vessels in the left eye and a normal fundus picture on the right (fig 1)
Magnetic resonance imaging (MRI) studies were performed, comprising gadolinium enhanced T1 weighted spin echo coronals with STIR sequences, T2 weighted spin axial and FLAIR sagittals, as well as magnetic resonance angiography (MRA). This showed a 3×4.5×6.5 cm angiomatous mass within the left sternocleidomastoid, with associated hemi-hypertrophy of the left facial tissues and hemi-mandible (fig 2). The tumour was isointense to muscle on T1 weighted images. It extended subcutaneously along the left temporalis muscle to the left temple and extends caudally to the lower border of the body of the mandible. Furthermore, the absence of signal void suggests that this is a predominantly slow flow lesion. It is particularly well seen on STIR sequences, which define its full extent, and it is notable that there is a deeper component extending into the pterygopalatine fossa, through the infraorbital fissure, providing the likely source of abnormal tissue seen in the left orbital apex and the origin of the left retinal racemose haemangioma. There was no intracranial midbrain extension or communication with cerebral vessels.
Wyburn-Mason syndrome is a vascular condition synonymous with Bonnet de Chaume Blanc syndrome and is characterised by the coexistence of facial, retinal, orbital, and central nervous system (CNS) arteriovenous malformations. Theron et al2 reviewed 80 cases of retinal AV anastomoses and found that 30% of patients had concomitant AV malformations in the CNS, a rate much lower than the 81% association reported by Wyburn-Mason.1 Bech and Jensen3also believe that the frequency of coexisting racemose haemangiomata of the retina and brain was over-reported in the Wyburn-Mason series, suggesting that the preponderance of patients with advanced retinal lesions in the original study made associated CNS lesions more common. Isolated intramuscular haemangiomas are rare congenital benign hamartomas,4 which comprise less than 1% of all haemangiomas in the body. Of those that do originate in muscle, only 15% originate in the head and neck region.
The absence of intracranial involvement in the presence of the other two characteristic features of this condition constitutes a rare clinical entity. Furthermore, the direct communication between the retinal racemose and intramuscular facial cavernous haemangiomas in our case, has not, to our knowledge been previously reported, and must be inordinately rare. This association may be consequential in our choice of therapeutic options for our patient.
Morbidity or early mortality in some Wyburn-Mason cases are secondary to the tendency of intracranial AV communications to bleed, leading to subarachnoid haemorrhage, neurological deficits and, in some cases, death. Ophthalmic manifestations may include visual loss secondary to intraretinal and macular haemorrhage, vaso-occlusive disease, neovascular glaucoma or vitreous haemorrhage.4–7 However, in most cases of abnormal retinal macrovessels, fluorescein angiography demonstrates stable non-leaking lesions. Management of patients with abnormal retinal macrovessels or “racemose” haemangiomas is difficult because of the heterogeneous modes of presentation. This may range from completely asymptomatic patients to those presenting with profound visual loss or neurological deficits. In the authors’ opinion, as a result of the high association with intracranial AV malformations (30–81%), imaging studies (MRI) should be carried out on all patients with retinal arteriovenous malformations. Fluorescein angiography may be carried out to demonstrate direct AV communication and to observe stability of the retinal vessels, but needs to be weighed against the risks of the procedure.
Because of the stability of most isolated retinal lesions, treatment from an ophthalmologist beyond routine periodic examination is probably unnecessary. However, failure to recognise specific neurological signs and symptoms and to make the appropriate referrals for radiological and neurological assessment, respectively, in cases of CNS involvement, may be a significant medicolegal pitfall. The important clinical correlates of Wyburn-Mason syndrome are shown in table 1. We would emphasise the need for an integrative approach, one that doesn’t consider retinal pathology in isolation, but that carries an awareness of the neurological and cutaneous manifestations of this condition.
In this particular case, owing to the direct communication of the retinal and facial vascular lesions, our options for treatment of the facial haemangioma may be limited by the risk of retinal vascular haemorrhage, occlusion, or thrombosis. The usual interventions which include injection sclerotherapy (she has had multiple treatments), embolisation of feeder vessels, laser photocoagulation, or proton beam irradiation may have implications for visual dysfunction. Direct surgical intervention may lead to massive and uncontrollable bleeding. In our asymptomatic young patient we have adopted a periodic review policy. But as adolescence and the social and cosmetic stigmata of a facial deformity make increasing assertions on our patient, we would welcome suggestions for definitive procedures that may be appropriate in the treatment of her condition.