Moyamoya Syndrome in a Pediatric Patient with ACTH Deficiency and Autoimmune Antibodies: Expanding the Endocrine–Autoimmune Spectrum — A Case Report and Literature Review

Moyamoya syndrome (MMS) is a rare, progressive cerebrovascular arteriopathy in which stenosis or occlusion of the terminal internal carotid arteries provokes fragile collateral formation. Immune and endocrine contributors are under-recognized in children. We report a 2-year-11-month-old boy with MMS, positive antinuclear antibodies (anti-Ro/SSA and anti-La/SSB), and genetically confirmed adrenocorticotropic hormone (ACTH) deficiency. He presented with progressive lethargy and focal motor seizures. Brain MRI demonstrated an acute right frontal gray-matter ischemic/inflammatory lesion with early Moyamoya changes. He received intensive care management (including antiepileptic therapy, antivirals for H1N1, and IVIG) and subsequently underwent staged indirect cerebral revascularization (pial synangiosis), with gradual neurological recovery. To contextualize the case, we summarize pediatric reports linking MMS to immune–endocrine abnormalities (autoantibodies, thyroid disease, growth-hormone axis disturbances, and rare adrenal-axis defects). These observations support a plausible “two-hit” model in which systemic immune–endocrine stressors accelerate an underlying occlusive arteriopathy through endothelial injury, prothrombotic tendencies, and hemodynamic instability. Early recognition of such systemic clues can expedite diagnosis, inform perioperative endocrine planning, and improve outcomes when combined with timely surgical revascularization.