Pitfalls in imaging: differentiating intravagal and carotid body paragangliomas.

We report a case of an intravagal paraganglioma and a case of a carotid body tumor to illustrate a variable presentation of the former in which it mimicked the latter on preoperative imaging. The atypical imaging features of the intravagal paraganglioma included inferior extension to the level of the carotid bifurcation and splaying of the internal and external carotid arteries, features that are similar to those seen in a case of carotid body paraganglioma. Proper differentiation of these lesions permits more appropriate preoperative counseling and surgical preparation. When using magnetic resonance angiography rather than catheter angiography, we advocate the inclusion of gadolinium contrast and three-dimensional time-of-flight techniques to better demonstrate the position of the tumor relative to the carotid bifurcation.