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Ophthalmology > PHAKOMATOSES
Wyburn-Mason Syndrome
Article Last Updated: Jul 24, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Ann E Bidwell, MD, Assistant Professor, Department of Ophthalmology, Northwestern University, Feinberg School of Medicine
Ann E Bidwell is a member of the following medical societies: American Academy of Ophthalmology
Editors: Gerhard W Cibis, MD, Director of Pediatric Ophthalmology Service, Clinical Professor, Clinical Professor, Department of Ophthalmology, Department of Ophthalmology, University of Kansas; Director, Children's Mercy Hospital, University of Missouri at Kansas City; Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles; J James Rowsey, MD, Director of Corneal Services, St Luke's Cataract and Laser Institute, Florida; Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri; Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Author and Editor Disclosure
Synonyms and related keywords:
Bonnet-Dechaume-Blanc syndrome, arteriovenous malformations, AV malformations, vascular abnormalities, vascular malformations, arteriovenous anastomoses, AV anastomoses, arteriovenous aneurysms, AV aneurysms, racemose aneurysms, retina, retinal vascular abnormalities
Background
Wyburn-Mason syndrome, also known as Bonnet-Dechaume-Blanc syndrome, is a rare condition characterized by arteriovenous malformations (AVMs) in the central nervous system (CNS) and the retina. Although these combined vascular abnormalities were recognized prior to the reports of Bonnet in 1937 and Wyburn-Mason in 1943, this condition is most frequently associated with Wyburn-Mason in deference to his work, which helped to initially categorize the syndrome. This condition is considered to be congenital, nonhereditary, and without sex or race predilection. Other vascular malformations may be present elsewhere in the body.
Pathophysiology
AVMs are characterized by variable alterations in capillary and arteriolar networks. Small vascular malformations may have only minor alterations within the capillary system and can be subtle, whereas large, racemose lesions are characterized by direct artery-to-vein communication, without interposing capillary or arteriolar elements.
Frequency
United States
Incidence is rare.
International
Incidence is rare.
Race
No known racial predilection exists.
Sex
No known sexual predilection exists.
Age
Wyburn-Mason syndrome is a congenital disorder. Larger AVMs causing visual or neurologic impairment are generally diagnosed earlier in life, whereas smaller lesions may not be diagnosed until later in life.
History
- Neurologic symptoms are extremely diverse because of variations in CNS lesion size, location, and configuration. Mental changes, headaches, seizures, visual field abnormalities, and cranial nerve paralyses are possible.
- Similarly, visual symptoms from retinal AVMs are related to the extent and location of the abnormal vascular process.
Physical
- Associated intracranial AVMs are more commonly found in patients with large, racemose retinal vascular anastomoses. CNS vascular lesions are typically homolateral to the involved eye, and they frequently involve the midbrain. In some cases, retinal lesions may result as an extension of an intracranial vessel malformation, extending anteriorly along the visual pathway, through the optic foramen, and along the optic nerve to the retina.
- In the retina, these AVMs may vary from small, abnormal vessel communications to extensive racemose involvement of the entire fundus, resembling a "bag of worms." Also referred to as cirsoid aneurysm, AV aneurysm, AV communication of the retina, racemose hemangioma, and AV varix, these abnormal retinal vessels usually remain stable and generally do not demonstrate leakage on fluorescein angiography. Rare associated ocular complications have been reported, which include macular hole, central retinal vein occlusion, neovascular glaucoma, macroaneurysmal abnormalities, retinal hemorrhage, and vitreous hemorrhage.
- Archer et al classified retinal AV anastomoses into 3 groups, as follows1:
- Group I is characterized by small arteriole-venule anastomoses, which may be subtle and difficult to detect clinically. These vessels usually are isolated to a sector or quadrant of the retina, and they often involve the macula.
- Group II represents direct artery-to-vein communication without intervening capillary or arteriolar elements. This group may represent an exaggerated form of the abnormalities included in group I, and it is likewise geographically segmented within the fundus.
- Group III includes malformations characterized by markedly convoluted, dilated, and tortuous retinal vessels extending throughout the entire fundus, making it virtually impossible to differentiate between arterial components and venous components. These eyes usually are severely vision impaired, which generally leads to earlier diagnosis in childhood. Patients in this group are at higher risk for systemic vascular involvement.
- Theron and coworkers reviewed 80 cases of retinal vascular anastomoses and found that 30% of these patients had concomitant AVMs in the CNS, a rate that is much lower than the 81% association reported by Wyburn-Mason.12 Bech and Jensen believe that the original statistics of Wyburn-Mason are too high, noting that many of Wyburn-Mason's patients had no angiographic or pathologic evidence of intracranial vascular malformations.2 It is possible that the preponderance of patients with more advanced retinal lesions in the Wyburn-Mason study made associated CNS lesions more common.
- Intracranial and retinal AVMs are occasionally accompanied by vascular malformations in the skin, oronasopharnyx, orbit, lung, and bone. Orbital involvement can present as mild proptosis, which is usually nonpulsatile. Although facial nevi were initially described in the original Wyburn-Mason paper, this association is infrequent.
Causes
Etiology of this syndrome is unknown.
Hemangioma, Capillary
Other Problems to be Considered
Retinal artery collaterals
Retinal vein collaterals
Retinal telangiectasis
Congenital retinal macrovessels
Imaging Studies
- Fluorescein angiography may further demonstrate the abnormal retinal vascular communications; most AVMs are stable, nonleaking processes.
- Magnetic resonance imaging (MRI)
- Magnetic resonance angiography (MRA) may be considered.
Histologic Findings
Histologically, retinal AVMs demonstrate vessels to have a fibromuscular media of varying thickness and wide fibrohyaline adventitial coats. Arteries and veins may be indistinguishable and, in some cases, occupy the entire thickness of the retina.
Medical Care
Because of the stability of the retinal lesions, treatment from an ophthalmologist usually is not necessary beyond routine, periodic ophthalmic examination. Likewise, CNS lesions are typically observed; however, radiotherapy or intravascular embolization may be considered in select patients.
Surgical Care
Although controversial, intracranial AVMs have been treated surgically in some cases.
Consultations
Referral for neurologic evaluation is indicated if a retinal AVM is diagnosed. Since intracranial vascular malformations are associated more commonly with larger retinal vascular lesions, it is reasonable to reserve more invasive diagnostic testing for those patients with advanced ocular findings or with specific neurologic abnormalities.
Further Outpatient Care
- Continued observation is indicated, although most lesions remain stable.
Complications
- Intracranial AVMs may hemorrhage, resulting in significant morbidity. AVMs within the mandible or the maxilla may result in excessive bleeding following dental procedures. Retinal AVMs may be complicated by vascular decompensation and ischemia-related changes. Complication rates depend on the extent and location of the lesions.
Prognosis
- Prognosis depends on the extent and location of the lesions.
Medical/Legal Pitfalls
- Failure to make appropriate neurologic referral after diagnosing retinal AV malformation
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| Media file 1:
Dilated arteriovenous system representing a well-compensated unilateral retinal arteriovenous malformation. This 12-year-old girl had 20/20 vision and a negative systemic evaluation. |
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Media type: Photo
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- Archer DB, Deutman A, Ernest JT, Krill AE. Arteriovenous communications of the retina. Am J Ophthalmol. Feb 1973;75(2):224-41. [Medline].
- Bech K, Jensen OA. On the frequency of co-existing racemose haemangiomata of the retina and brain. Acta Psychiatr Scand. 1961;36:47-56. [Medline].
- Bonnet P, Dechaume J, Blanc E. L'aneurysme cirsoide de la retine (aneurysme vasemeaux). J Med Lyon. 1937;18:165-178.
- Brown GC, Donoso LA, Magargal LE, Goldberg RE, Sarin LK. Congenital retinal macrovessels. Arch Ophthalmol. Sep 1982;100(9):1430-6. [Medline].
- Cameron ME, Greer CH. Congenital arterio-venous aneurysm of the retina. A post mortem report. Br J Ophthalmol. Oct 1968;52(10):768-72. [Medline].
- Chan WM, Yip NK, Lam DS. Wyburn-Mason syndrome. Neurology. Jan 13 2004;62(1):99. [Medline].
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- Lester J, Ruano-Calderon LA, Gonzalez-Olhovich I. Wyburn-Mason syndrome. J Neuroimaging. Jul 2005;15(3):284-5. [Medline].
- Mansour AM, Walsh JB, Henkind P. Arteriovenous anastomoses of the retina. Ophthalmology. Jan 1987;94(1):35-40. [Medline].
- Mansour AM, Wells CG, Jampol LM, Kalina RE. Ocular complications of arteriovenous communications of the retina. Arch Ophthalmol. Feb 1989;107(2):232-6. [Medline].
- Nüssel F, Wegmüller H, Huber P. Comparison of magnetic resonance angiography, magnetic resonance imaging and conventional angiography in cerebral arteriovenous malformation. Neuroradiology. 1991;33(1):56-61. [Medline].
- Theron J, Newton TH, Hoyt WF. Unilateral retinocephalic vascular malformations. Neuroradiology. 1974;7(4):185-96. [Medline].
- Wyburn-Mason R. Arteriovenous aneurysm of midbrain and retina, facial naevi and mental changes. Brain. 1943;66:163-203.
Wyburn-Mason Syndrome excerpt Article Last Updated: Jul 24, 2007
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