Moyamoya disease complicated by Graves' disease and type 2 diabetes mellitus: report of two cases.

The pathogenesis of moyamoya disease remains unknown. Examination of diseases concurrent with moyamoya disease may offer a clue to clarify the pathogenesis. Coexistence of moyamoya disease, Graves' disease, and diabetes mellitus is very rare. We present the first cases in the literature. A 38-year-old man with moyamoya disease and a 43-year-old woman with quasi-moyamoya disease, both concurrent with Graves' disease and type 2 diabetes mellitus, are presented. Both patients underwent antithyroid therapy and revascularization. After normalization of thyroid hormones level and blood glucose level followed by revascularization, the symptoms of cerebral ischemia were improved. The common etiological factors of these diseases are discussed. Genetic and autoimmune factor appeared to be involved in the pathogenesis of the three diseases, which may suggest that these factors play important roles in the pathogenesis of moyamoya disease. Further studies are required to define the pathogenesis of moyamoya disease, especially in cases with comorbidities as in the present patients.