Cerebral vascular malformations constitute one of the key abnormalities in children with PHACE syndrome, which is characterized by Plaque like cutaneous hemangiomas, Posterior fossa abnormalities, arterial Cerebrovascular and Eye abnormalities, with or without Sternal clefts (PHACES when sternal clefts are present), and associated midline anomalies. Both moyamoya arteriopathy and intracranial aneurysms have been reported in children with this syndrome. Herein, we report the successful treatment of a growing left posterior-communicating artery aneurysm arising from an aberrant left internal carotid artery (LICA) with balloon assisted coiling (BAC) in a child with PHACE syndrome. We circumvented the limitations posed by the narrow caliber of the proximal LICA, by successfully navigating a coiling microcatheter from the basilar artery into the LICA <i>via</i> a persistent trigeminal artery. BAC was then achieved using a Scepter Mini balloon microcatheter for aneurysm neck remodelling.