Computed tomography angiography lightbulb sign: Characteristic enhancement pattern on neck computed tomography angiography in differentiating paraganglioma from schwannoma of the carotid space.

It is important to correctly distinguish paragangliomas from other tumors such as schwannomas in the preoperative assessment of head and neck tumors because paragangliomas have a propensity to bleed profusely during surgery. Therefore, preoperative embolization is often required while with schwannomas preoperative embolization is generally not required. Occasionally, schwannomas can mimic paragangliomas on routine computed tomography and magnetic resonance imaging of the neck. In this study, we retrospectively evaluated the computed tomography angiography of the neck of 10 patients with carotid space tumors. Seven patients had pathologically proven paraganglioma while three patients had schwannomas. We describe the "computed tomography angiography lightbulb sign" as avid homogeneous enhancement in the arterial phase which can accurately distinguish these entities.