Aneurysmal bone cysts (ABCs) arising from vascular malformation are extremely rare, and none have been reported in the literature in English till now. We report a very rare case of secondary ABC of left temporal bone in a 5-year-old Caucasian boy who presented with a left sudden facial palsy associated with a painless non-tender mass of the left temporo-parietal region. The computed tomography (CT) and magnetic resonance imaging (MRI) features were suggestive of ABC secondary to a capillary venous malformation, with concurrent involvement of the squamous, mastoid, and petrous portions of the temporal bone. Surgical resection was performed. On follow-up, the patient was found to be doing well.