Progressive stenosis and radiological findings of vasculitis over the entire internal carotid artery in moyamoya vasculopathy associated with graves' disease: a case report and review of the literature.

Background: Moyamoya vasculopathy (MMV) associated with Graves' disease (GD) is a rare condition resulting in ischemic stroke accompanied by thyrotoxicity. Radiological findings of vasculitis have been reported in the walls of distal internal carotid arteries (ICAs) in these patients; however, no reports have described in detail the processes of progression of the lesions in the proximal ICA. Moreover, treatments to prevent recurrence of ischemic stroke and progression of MMV have not yet been sufficiently elucidated.

Case Presentation: We report a progressive case of MMV associated with GD and review the literature to clarify relationships among recurrence, progression, thyrotoxicity and treatment. Our patient developed cerebral infarction during thyrotoxicity with no obvious stenosis of ICAs. Five months later, transient ischemic attacks recurred with thyrotoxicity. Antiplatelet therapy and intravenous methylprednisolone stopped the attacks. Stenosis of the left ICA from the proximal to distal portion and champagne bottle neck sign (CBN) were found. She declined any surgery. Afterward, gradual progression with mild thyrotoxicity was observed. Eventually, we found smooth, circumferential, concentric wall thickening with diffuse gadolinium enhancement of the left ICA from the proximal to the distal portion on T1-weighted imaging, suggesting vasculitis radiologically. The clinical and radiological similarities to Takayasu arteritis encouraged us to provide treatment as for vasculitis of medium-to-large vessels. In a euthyroid state and after administration of prednisolone and methotrexate, improved flow in the cerebrovascular arteries on magnetic resonance angiography was observed. Based on our review of the literature, all cases with recurrence or progression were treated with anti-thyroid medication (ATM) alone and accompanied by thyrotoxicity. CBN was observed in all previous cases for which images of the proximal ICA were available.

Conclusions: We report the details of progressive stenosis from a very early stage and radiological findings of vasculitis over the entire ICA in MMV associated with GD. Cerebral infarction can occur with no obvious stenosis of the ICA. We treated the patient as per vasculitis of a medium-to-large vessel. Management of GD by ATM alone seems risky in terms of recurrence. Adequate management of GD and possible vasculitis may be important for preventing recurrence and progression.