An unexpected cause of upper airway obstruction.

A three-year-old boy with a swelling on the right side of his neck was suspected of having a parapharyngeal abscess after clinical examination and CT scan (computed tomography scan) of this region. Later it became clear, that the swelling was caused by an aneurysm of the internal carotid artery. This case report describes the pitfalls and difficulties encountered in the diagnostic course and treatment planning.