Malignant Tumors of the Mobile Tongue Workup

• Because the incidence of distant metastases at presentation is low, the only laboratory workup needed should be directed at the evaluation of the patients' underlying chronic medical conditions. A complete blood cell count is a useful general screen that helps the consulting internist establish if further testing is warranted.
• In a patient with a suspected bleeding diathesis, investigations may also include tests of prothrombin time (PT), activated partial thromboplastin time (aPTT), and international normalized ratio (INR).

• Dental radiographs: Periapical dental films provide fine details and are the most useful for detecting minimal invasion of the mandible, compared with CT scans and panoramic radiographs showing gross bony destruction.
• Bone scan: Bone scanning has no role in the evaluation of mandibular involvement by tumors, nor has it been considered useful in the patient's general survey for bony metastases.
• Chest radiograph: This may be used as the sole radiographic study in the evaluation for distant metastases because the incidence of distant metastases at presentation is low.
• CT scan and MRI: Radiologic evaluation with a CT scan and MRI has revolutionized the assessment of patients with head and neck tumors. Because of the higher soft tissue resolution with an MRI, the assessment of the mobile tongue may be facilitated. Computerized tomography is an excellent modality to evaluate the patient's nodal status. The evaluation of nodal number, size, location, contour and necrosis is helpful in staging. Due to its imaging characteristics tongue cancer may be difficult to pick up on computerized tomography, unless the tumor leads to deformity of the extrinsic tongue musculature or the anatomy of the floor of mouth or tongue base.
• Involvement of the extrinsic tongue musculature and direct extension in the submandibular glands and the base of tongue can be revealed with MRI.

  • Response to therapy also may be evaluated more thoroughly.
  • As part of the staging and management processes, confirmation of nodal disease, vascular distortion or involvement, bony destruction, or potential space involvement aids in the diagnosis.
  • In his 1991 paper, Shaha demonstrated that physical examination findings were accurate at predicting the extent of mandibular involvement 90% of the time in patients with floor of the mouth cancer.^[2] Radiographs and CT scans were not as accurate and correctly predicted mandibular involvement in only 70% of patients.
• MRI: Both CT scan and MRI are generally reliable for detecting the extent of soft tissue and bony involvement in persons with oral cavity carcinoma. However, MRI has several potential advantages in staging tumors of the oral cavity.

  • Tissue contrast between tumor and normal musculature is higher on T2-weighed images.
  • No beam artifact from amalgam or other dental material is noted.
  • Imaging can be performed in sagittal, coronal, and axial planes.
  • Contrast between postirradiation fibrosis and recurrent tumor is improved on T2-weighed images.
• Positron emission tomography-CT imaging:

  • The combination of positron emission tomography (PET) and CT is a new diagnostic and staging modality in the evaluation of the patient with head and neck cancer.
  • PET scans are used most often to reveal cancer and to examine the effects of cancer therapy by characterizing biochemical changes in the cancer. These scans can be performed on the whole body or can be localized to the head and neck.
  • A PET scan demonstrates the biological function of the body before anatomical changes take place, while the CT scan provides information about the body's anatomy, such as size, shape, and location. By combining these 2 scanning technologies, a PET-CT scan enables physicians to more accurately diagnose and identify cancer and its extent.
  • These can be used as a tool in the initial evaluation of the patient who presents for initial staging, as well as for evaluating response to treatment.

• Tumor biopsy: A sample of the lesion may be obtained in the clinical setting or as part of the endoscopic evaluation of the tumor. Proper sampling is required in order to allow the pathologist to evaluate viable tumor cells. The vast majority of biopsy findings reflect the presence of squamous cell carcinoma. In fewer instances, minor salivary gland malignancies and sarcomas are discovered.
• Panendoscopy: The routine use of this procedure, which includes a bronchoscopy, esophagoscopy, and laryngoscopy, has been the subject of much controversy.^[3] It allows for the complete evaluation of the upper aerodigestive tract and helps rule out the presence of a metachronous tumor. The mucous membranes of the upper aerodigestive tract are carefully evaluated, and biopsy samples of any abnormal-looking areas are taken for assessment. An intermediate view is obtained by performing a tumor-specific endoscopy, whereby the anesthetized patient in a relaxed state can have the oral cavity examined with less difficulty. After completing the evaluation, the tumor is staged.

Squamous cell carcinoma is by far the most common epithelial malignancy of the tongue, and nonsquamous cell cancers comprise fewer than 3% of all lingual malignancies. Also, the 2 prominent variants of oral squamous cell carcinomas that may be present are referred to as verrucous carcinoma and sarcomatoid squamous cell carcinoma.

Verrucous cell carcinomas have been described as a unique form of squamous cell carcinoma related to human papillomavirus infection. In its early phases, the tumor may be subclinical and asymptomatic as a verruciform growth phase that lasts several years. In other patients, the lesion may appear suddenly or as a slowly growing lesion that has a sudden and rapid growth phase.

The macroscopic appearance of these lesions depends on the duration of the lesion, the amount of keratinization, and the changes in the adjoining mucosa. A fully developed lesion has the appearance of an exophytic bulky lesion that is gray to grayish-red and has a rough, shaggy, or papillomatous surface.

Microscopically, these tumors are broadly based and invasive through papillary fronds. They are composed of highly differentiated squamous cells lacking frank cytologic criteria of malignancy with rare mitoses. The surface of the lesion is covered with compressed invaginating folds of keratin layers. Typically, a blunt pushing margin and astromalike inflammatory reaction are seen.

Sarcomatoid carcinomas are also referred to as pseudosarcoma, pseudosarcomatous squamous cell carcinoma, pleomorphic carcinoma, metaplastic carcinoma, and the spindle variant of epidermoid carcinoma. The tumor manifests as a rapidly growing, polypoid, and bulky mass, often in a site exposed to prior irradiation. The histogenesis of these tumors is not clear. In general, because of their heterogeneous nature, microscopic interpretation of these tumors is highly subjective. In addition, sampling limitations are inherent to any fine structural analysis. Electron microscopy findings from these tumors are likely to be of value only if epithelial features are present within the spindle cells.

Malignancies of salivary gland origin also may occur, with adenoid cystic carcinomas^[4] and mucoepidermoid carcinomas predominating in histological subtypes. Relative to the palate, minor salivary gland malignancies of the tongue are rare.

Oral mucosal melanomas to the tongue are rare relative to other oral cavity sites such as the palate, alveolar gingivae, and lips. Virtually any malignancy can metastasize to the tongue. Statistically, carcinomas of the breast, lung, kidney, and adrenal gland are the most common.

The staging of oral cavity cancers is accomplished using the 1998 TNM system developed conjointly by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (IUCC).

• The primary tongue tumor (T) has the following descriptions:

  • T1: Tumors are 2 cm or smaller in greatest dimension.
  • T2: Tumors are larger than 2 cm but not larger than 4 cm in greatest dimension.
  • T3: Tumors are larger than 4 cm in dimension.
  • T4: Tumors involve adjacent structures.
  • T4a: Tumor invades adjacent structures (eg, cortical bone, deep [extrinsic] muscle of tongue [genioglossus, hyoglossus, palatoglossus, styloglossus], or facial skin).
  • T4b: Tumor invades masticator space, pterygoid plates, or skull base and/or encases internal carotid artery.
• The node (N) staging system also uses the AJCC and UICC system and is as follows:

  • N0: No nodal metastasis is present.
  • N1: A single ipsilateral node is smaller than 3 cm in greatest dimension.
  • N2a: Metastasis in a single ipsilateral lymph node that is larger than 3 cm but not larger than 6 cm in dimension.
  • N2b: Multiple ipsilateral nodes are smaller than 6 cm in greatest dimension.
  • N2c: Bilateral or contralateral nodes are smaller than 6 cm in greatest dimension.
  • N3: Any node is larger than 6 cm in greatest dimension.
• The stage groupings are also defined by the AJCC as follows: Table. AJCC Stage Groupings

  (Open Table in a new window)

  	T1	T2	T3	T4
  N0	I	II	III	IV
  N1	III	III	III	IV
  N2	IV	IV	IV	IV
  N3	IV	IV	IV	IV