Squamous Cell Carcinoma (SCCa) (Tongue)

Diagnosis Definition

• >90% of oral cavity (including anterior tongue and floor of mouth), pharynx (nasopharynx, oropharynx, including posterior tongue, and hypopharynx), and laryngeal malignancies are squamous cell carcinoma (SCCa); tumors are staged by the TNM (tumor, nodes, metastases) classification
• Risk factors for SCCa include long-term overuse of alcohol and tobacco and human papillomavirus (HPV)
• Approximately 65% of patients with oropharyngeal SCCa present with metastatic cervical lymphadenopathy; the most frequent sites of SCCa causing regional metastases are base of the tongue and tonsil
• SCCa in the base of the tongue often manifests with dysphagia, odynophagia, or the sensation of a mass

Imaging Findings

• SSCa of the tongue should be evaluated for 1) submucosal involvement, 2) involvement of the intrinsic muscles of the tongue, 3) crossing of the midline, 4) invasion of the pre-epiglottic fat, 5) osseous involvement, 6) perineural spread, and 7) lymphadenopathy
• MRI is better than CT for characterizing the primary tumor and perineural spread due to less dental amalgam artifact and better soft tissue resolution
• Subtle cortical erosions are best detected with CT, whereas marrow involvement is best assessed with MRI
• MRI findings of osseous involvement on T1 imaging include loss of low signal cortex, marrow replacement with intermediate signal tumor, and tumor enhancement (on fat-suppressed sequences)
• Pathologic lymph nodes are round and enlarged (maximum longitudinally): >8 mm (retropharyngeal), >15 mm (jugulodigastric), and >10 mm all others; size criteria is decreased to 8-11 mm axially and if >3 enlarged nodes in same drainage area; poorly defined nodal margins and soft-tissue stranding around nodes indicates extracapsular spread

KEY IMAGES

Pearls

• Nodal involvement is the single most important prognostic indicator of head and neck SCCa
• Evaluation of the midline of the tongue and the contralateral neurovascular bundle is important for surgical planning because any invasion of the midline precludes hemiglossectomy

References

1. Trotta BM, Pease CS, Rasamny JkJ, Raghavan P, Mukherjee S.  Oral cavity and oropharyngeal squamous cell cancer: key imaging findings for staging and treatment.  RadioGraphics.  2011; 31:339–354