Tap on and choose 'Add to Home Screen' to create a shortcut app

Tap on and choose 'Add to Home Screen/Install App' to create a shortcut app

Pathology of Moyamoya Disease in Children

This page was last updated on August 20th, 2019


  • Primary event stenosis of distal internal carotid artery: The etiology of stenosis of distal internal carotid artery or its branches are unknown. Enlargement of basal perforators with occasional microaneurysm formation and bleeding, leptomeningeal and other anastomotic vessel formation, and cerebral infarction are regarded as secondary events to the stenosis or occlusion of the distal internal carotid artery and its primary branches.
  • Clinical manifestations due to ischemia: Transient ischemic symptoms are results of decreased cerebral perfusion. Patients with Moyamoya Disease are sensitive to hyperventilation that causes physiologic cerebral arterial narrowing in normal condition. Seizure may accompany ischemia, infarction or bleeding. Headache may reflect compensatory vasodilatation of cerebral arterial trees with chronic or compensated cerebral ischemia.

Molecular/genetic Pathology

  • RNF213 mutation: In North America, only a small minority of pediatric moyamoya cases (<5%) appear to have clear mutational associations, unless the child has Asian heritage (30-40 % of Asians have RNF213 mutations) (6,14,16,38).  The presence of a RNF213 mutation with moyamoya has marked significance for familial screening, as data suggests that familial penetrance is ~23% and, if an individual carries the mutation, there is a near 50% likelihood of manifesting arteriopathy (38,42).
  • Other mutations: There are several other mutations that can result in Moyamoya Disease. They are more rare but may be detected by specific clinical or radiographic phenotypes (ACTA2 carriers with distinctive stellate arteries branching from a dilated proximal internal carotid, GUCY mutations with achalasia, etc.) (6,15,16,38,42,44,46,62).
Mutations associated with Moyamoya Disease (15,16,44)
ACTA2 R179

Primary Histopathology

  • Narrowing artery: The vessels of stenosis show narrowing of external and luminal diameters of arteries with thickening of intima.  This is due to fibro-cellular thickening with smooth muscle cell proliferation of intima, irregular undulation of the internal elastic lamina and attenuation of the media.  Inflammatory cell infiltration and lipid deposits are absent or rare (10,41).

Your donations keep us going

The ISPN Guide is free to use, but we rely on donations to fund our ongoing work and to maintain more than a thousand pages of information created to disseminate the most up-to-date knowledge in the field of paediatric neurosurgery.

By making a donation to The ISPN Guide you are also indirectly helping the many thousands of children around the world whose treatment depends on well-informed surgeons.

Please consider making a donation today.

Use the app

The ISPN Guide can be used as a standalone app, both on mobile devices and desktop computers. It’s quick and easy to use.

Fully featured

Free registration grants you full access to The Guide and host of featured designed to help further your own education.

Stay updated

The ISPN Guide continues to expand both in breadth and depth. Join our mailing list to stay up-to-date with our progress.