A distal anterior cerebral artery aneurysm in infant: disappearance and reappearance of the aneurysm

The incidence of intracranial aneurysms in childhood is rare, especially in infancy. Spontaneous thrombosis of a cerebral aneurysm in a child is very rare, particularly in a non-giant aneurysm. We report a case of a 1-month-old girl with a distal anterior cerebral artery aneurysm which disappeared spontaneously after subarachnoid hemorrhage and reappeared 6 months later. Surgical resection of the aneurysm was performed and she discharged uneventfully 10 days later. Histological examination revealed an aneurysm with a fibrous muscular layer, absence of the internal elastic lamina and partial hypertrophy of the intimal layer. Though the pathogenesis of this aneurysm is uncertain, two hypotheses are discussed.