Table 1.

Differential diagnosis of chordoma in the petrous mastoid region

Imaging	Chordoma	Jugular glomus tumors	Middle ear cancer	Chondrosarcoma	Solitary fibroma tumor
CT	Irregular low-density mass with calcification and well-defined boundaries, expansive growth, and the surrounding bone is absorbed and destroyed	Low-density mass, osteolytic destruction with flaky calcification	Soft-tissue density mass with ill-defined, surrounding bone absorption and destruction	Both feature calcification and surrounding bone infiltration in the mass	Soft-tissue density mass with well-defined boundaries, the most of adjacent bones show compressive changes
MRI	Obvious hyperintensity and a “beehive-like” appearance on T2WI, and honeycomb sign of obvious enhancement	A “salt and pepper sign” on T2WI, and significant enhancement	Soft tissue mass with the middle ear as the center, an unclear boundary, and enhanced inhomogeneous enhancement	Significantly high signal on T2WI, and inhomogeneous enhancement	Attached to the dura mater with, obvious enhancement, and hypointense area (collagen fibers) on T2WI

CT: Computed tomography; MRI: Magnetic resonance imaging; T2WI: T2-weighted imaging.