This case is a large carotid space-based mass with displacement of the carotid bifurcation.

The MRI signal characteristics and enhancement pattern were most suggestive of a schwannoma.  The centering on carotid space would indicate it is vagal (CN 10) nerve-derived, however clinically the patient has a hypoglossal (CN 12) palsy.

At surgery the explanation was evident - the hypoglossal nerve was tightly stretched over the lateral aspect of the mass.