Oral cavity and pharynx.

Imaging of the oral cavity and pharynx often is required in three settings: assessment of an inflammatory mass in association with odontogenic, tonsillar, or pharyngeal infections; determination of the cause of a submucosal mass; and staging of squamous-cell carcinomas. Spread of infection from the oral cavity and pharynx can lead to abscesses in the masticatory space, the retropharyngeal compartment, and in a parapharyngeal location. Submucosal masses include congenital cysts (thyroglossal and dermoid), benign neoplasms (hemangioma, schwannomas, pleomorphic adenomas juvenile angiofibromas), inflammatory cysts (mucous retention cysts, ranulas), and pseudotumors (osteophytes, carotid arteries). Staging of squamous-cell carcinomas must focus on deep invasion, spread to the brain, nerves, mandible, prevertebral muscle, and pre-epiglottic fat.