Squamous cell carcinoma of the external auditory canal

There is an infiltrative aggressive mass centered at the left middle ear. It occupies all three left middle ear cavities (epi-, meso- and hypotympanium) and causes complete destruction and erosion of the left middle ear ossicular chain. It demonstrates intermediate signal intensity on both T1 and T2 sequences (compared to grey matter). It shows heterogeneous enhancement post-contrast with scattered multiple small ring-enhancing foci/collections throughout this mass. There is no salt-and-pepper appearance on either T1 post-contrast or T2 sequences. On the DWI/ADC sequences, this mass shows restricted diffusion.

• Superiorly, the mass invades and extends into the left middle cranial fossa via erosion of both the left tegmen tympani and tegmen mastoideum with enhancing dura at the left temporal region.

• Medially, it displaces the left parapharyngeal space and left carotid space but does not encase the left internal carotid artery.

• Posteriorly, the mass encases and compresses the left internal jugular vein. The mass extends to the cortical margin of the left mastoid bone, but there is no obvious intracranial mass extension into the posterior cranial fossa. It erodes the stylomastoid segment of the left facial nerve with associated abnormal enhancement of the labyrinthine segment of the left facial nerve.

• Anteriorly, the mass abuts the condylar process of the left mandible and extends into the left temporomandibular joint with abnormal bone marrow enhancement post-contrast. There is loss of normal post-condylar fat signal intensity. Abnormal bone marrow signal intensity and bony erosion within the left styloid process is in keeping with infiltration.

• Laterally, the mass extends to the middle of the left external ear canal. Normal tympanic membrane is not seen.

• Inferiorly, the mass has no clear fat plane with the superior aspect of the left parotid salivary gland.

There is relative absence of significant fat stranding surrounding the mass, especially at the left parapharyngeal space.

There is obstructive fluid opacification within the left mastoid air cells. The rest of the paranasal sinuses and right mastoid air cells are clear.

There is no abnormal intra-axial brain lesion or signal intensity, especially at the left temporal lobe and left cerebellum.

The inner ear structures (left cochlea, vestibule and semi-circular canals) show normal signal intensity on the T2 sequence.

There are subcentimeter left level II cervical lymph nodes.

Homogeneously enhancing soft tissue mass centered at left middle ear cavity/jugular foramen. Bone erosion involves the left temporal bone, tegmen tympani, tegmen mastoideum with intracranial extension into the left middle cranial fossa and adjacent enhancing dura. Lack of fat stranding surrounding this mass.