Oral Cavity and Oropharyngeal Squamous Cell Cancer: Key Imaging Findings for Staging and Treatment Planning

Abstract

The imaging findings in squamous cell carcinoma (SCC) of the oral cavity and oropharynx vary widely, depending on the site of origin of the primary tumor and the extent of its involvement of other regions. Knowledge of the complex anatomy of the oral cavity and oropharynx, as well as the most common routes by which SCC spreads from various anatomic sites, allows the radiologist to accurately determine the extent of disease and help clinicians plan appropriate treatment. SCCs that originate in the oral cavity tend to behave differently than those that originate in the oropharynx, with the latter group exhibiting more aggressive growth. Furthermore, primary tumors in certain anatomic subsites within the oral cavity or oropharynx have a greater propensity to spread by direct extension along muscle, bone, or neurovascular bundles or to be disseminated along lymphatic drainage pathways to regional or distant nodes. Imaging findings of deep muscular, neurovascular, osseous, or nodal involvement are indicative of an advanced stage of disease for which management options are limited.

Radiographic Imaging of Human Papillomavirus Related Carcinomas of the Oropharynx

“…The richness of the lymphatic drainage for this location helps explain the propensity for bilateral nodal involvement (approximately 30 %) [8]. Nodal levels most commonly affected are II, III, and IV.…”

“…Mucosal or submucosal disease spread to the hypopharynx and nasopharynx also occurs. SCC of the tonsillar complex is commonly (66-76 %) associated with positive lymph nodes at the time of diagnosis: the levels II, III and IV ipsilateral nodes are most commonly affected [7][8][9][10].…”

“…4). If the tumor extends laterally, the pterygomandibular raphe and anterior tonsillar pillar can be reached; from there the tumor can spread in a predictable fashion along those tissue planes [7][8][9][10].…”

“…Given the rich lymphatic drainage of the OP, OP SCC often present with nodal disease (up to 65 %), most commonly with BOT primary lesions followed in descending order of incidence by tonsil, oropharyngeal wall and soft palate [8]. Patients may present with an identifiable mucosal lesion, a nodal mass, or both.…”

“…When tumor invades bone or cartilage, MRI will show replacement of the normal marrow or cartilage signal with signal that is isointense/isoenhancing to tumor. Unfortunately, recent dental extraction, post radiation treatment fibrosis, and osteoradionecrosis can cause false positives for bone involvement on MRI [8].…”