Management of moyamoya syndrome in patients with Noonan syndrome

• Noonan syndrome is rarely associated with cerebrovascular abnormalities.
• Only 1 report exists of indirect bypass for combined moyamoya and Noonan syndromes.
• We report the first treated cases of adult moyamoya with Noonan syndrome.
• We describe the first two direct bypasses in patients with both syndromes.
• Surgical revascularization is safe and effective in patients with both syndromes.

A few isolated reports have described an association between Noonan syndrome and cerebrovascular abnormalities, including moyamoya syndrome. These reports have been limited to pediatric patients presenting with recurrent transient ischemic attacks (TIA) or headaches. Management has primarily been pharmacologic, with only one prior report of surgical revascularization to our knowledge. We report four cases of Noonan syndrome patients presenting with headaches and/or sensorimotor strokes in childhood that caused unilateral sensorimotor impairment. Cerebral angiography and MRI revealed bilateral moyamoya syndrome. All patients underwent successful bilateral extracranial-to-intracranial revascularization. The first patient was a 10-year-old girl who presented following a hemorrhagic stroke and recovered well after indirect bypass. The second patient was an adult with a history of childhood stroke whose symptoms progressed in adulthood. She underwent a direct bypass and improved, but continued to experience TIA at her 4 year follow-up. The third patient was a 7-year-old girl with headaches and a new onset TIA who failed pharmacological therapy and subsequently underwent bilateral indirect bypass. The fourth patient was a 24-year-old woman with worsening headaches and an occluded left middle cerebral artery from unilateral moyamoya syndrome. A left sided direct bypass was completed given delayed MRI perfusion with poor augmentation. To our knowledge these are the first reported surgical cases of combined Noonan and moyamoya syndrome. These cases highlight the need to recognize moyamoya syndrome in patients with Noonan syndrome. Early surgical revascularization should be pursued in order to prevent symptom progression.