Teaching Case

Recent appearance of left mandibulary pain, not resolving under current sedation. Physical examination revealed an ulcerative and infiltrative lesion of the anterior floor of the mouth, adherent to the gingiva. Biopsy disclosed a well differentiating, keratinizing squamous cell carcinoma CT and MR were obtained in the pre therapeutic workup.

Squamous cell carcinoma of the oral cavity represent less than 1% of all tumors. They are due to alcohol and tobacco exposure. The diagnosis is suspected by the patient or a physician (dentist). Most often the histological diagnosis when the patient is referred for imaging workup. Imaging plays an essential for tumor mapping. It shows the relationship with the main supporting structures of the oral cavity : muscles of the floor of the mouth (mylohyoid, geniohyoid, anterior belly of digastic muscles) and tongue (genioglossus), and lingual pedicle. Imaging is particularly important to evaluate the bone. The cortical bone is seen at best on CT, with bone window setting. The medullary bone is evaluated on T1-weighted MR sequence. Normal medullary bone is displayed with high signal intensity. In case of tumor invasion, the medullary bone is replaced by low signal intensity areas. However, this finding is nonspecific and is also found in inflammatory and infectious condition, a frequent problem in this population with poor dental status.