Evaluation

The quality of high-resolution computed tomography (CT) scans has improved, resulting in a resolution that gives fine bone detail. Bone erosion by the tumor can readily be seen. However, when the CT scan shows abnormal soft tissue, the question of inflammation versus malignancy is not as certain. Arriaga et al.3 presented a retrospective review of CT scans of patients with squamous cell carcinoma of the external auditory canal and temporal bone. T1 lesions have tumor limited to the external auditory meatus without bony erosion or soft tissue extension. T2 lesions would be limited to bone erosion of the external bony canal and < 0.5-cm soft tissue extension. This category would include lesions extending through preformed pathways such as cartilaginous fissures of the bony cartilaginous junction of the external auditory meatus. T3 lesions would demonstrate full thickness erosion of the osseus external auditory meatus with <0.5 cm soft tissue involvement, tumor involving the middle ear mastoid, or facial nerve paralysis. T4 would be lesions eroding the cochlea, petrous apex, medial wall of the middle ear carotid canal, jugular foramen, or dura with >0.5 cm of soft tissue extension.

A careful clinical examination follows the histologic diagnosis of squamous cell carcinoma. The canal is evaluated for the location of the ulceration or granulation tissue. Evaluation of the tympanic membrane is important; however, it will not be possible to see the tympanic membrane in 50% of cases. Depth of disease in the canal can be helpful. Anterior lateral disease may extend into the glenoid fossa or the superficial lobe of the parotid gland. Anterior medial disease may extend into the deep lobe of the parotid gland. Posterior disease may spread to the postauricular lymph nodes.

A complete head and neck examination is accomplished, including cranial nerves, and the parotid, neck, and postauricular area. Imaging studies are performed. The thin-cut high-resolution CT scan is most important. The magnetic resonance imaging (MRI) scan may be helpful; however, false-positive soft tissue involvement such as brain extension may be seen. The CT scan is evaluated with the assistance of a temporal bone neuroradiolo-gist. Careful attention is directed to the bone of the external auditory canal, the tympanic membrane, and the ossicles. Disease limited to these areas would be staged as T1 or T2, as noted by Arriaga et al.3 There is no reliable sign to differentiate extension of disease through the tympanic membrane, and lateral ossicles as inflammatory granulation tissue or squamous cell carcinoma.

The structures of the medial wall of the middle ear, mas-toid, dural plates, and otic capsule are evaluated. Disease in this area would be staged T3. The carotid canal, jugular bulb, foramen, and skull base are evaluated. Involvement of these structures would be staged T4.

The area of the glenoid fossa, the mandibular condyle, and the parotid gland is evaluated by CT scan and MRI scan. Consultations with colleagues in head and neck, neurotology, and neurosurgery are obtained as required. A treatment plan is outlined by the entire team.

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