Malignant Tumors of the Mobile Tongue Workup

Updated: Mar 01, 2021
  • Author: Benoit J Gosselin, MD, FRCSC; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Workup

Laboratory Studies

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 count (CBC) 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).

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Imaging Studies

See the list below:

  • 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 and MRI scans: 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 scan, the assessment of the mobile tongue may be facilitated with this modality. 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. [6] 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.

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Diagnostic Procedures

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, an esophagoscopy, and a laryngoscopy, has been the subject of much controversy. [1] 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.

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Histologic Findings

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 [7] 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.

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Staging

As described in the June 5, 2018, update of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, Eighth Edition, primary oral cavity tumors are staged as follows. [8]

Criteria for primary tumor (T) classification

These include the following [8] :

  • T1 - Tumors are 2 cm or smaller, with a depth of invasion of 5 mm or less
  • T2 - Tumors are 2 cm or smaller, with a depth of invasion of over 5 mm, or tumors are greater than 2 cm but do not exceed 4 cm, with a depth of invasion of 10 mm or less
  • T3 - Tumors are larger than 2 cm but no bigger than 4 cm, with a depth of invasion of over 10 mm, or tumors are over 4 cm in size, with a depth of invasion of 10 mm or less
  • T4 - This involves moderately or very advanced local disease
  • T4a - This involves moderately advanced local disease; tumors are over 4 cm, with a depth of invasion of over 10 mm, or tumors have invaded only adjacent structures (eg, having advanced through the cortical bone of the mandible or maxilla or demonstrated maxillary sinus or facial skin involvement)
  • T4b - Tumors have invaded the masticator space, pterygoid plates, or skull base and/or encased the internal carotid artery.

Criteria for clinical nodal classification

These include the following [8] :

  • N0: No nodal metastasis is present
  • N1: The metastasis occupies a single ipsilateral node and is no more than 3 cm in the greatest dimension; no extranodal extension is present
  • N2a: The metastasis occupies a single ipsilateral lymph node; exceeds 3 cm, but not 6 cm, in the greatest dimension; and does not involve extranodal extension,
  • N2b: Metastases, none beyond 6 cm in the greatest dimension, occupy multiple ipsilateral lymph nodes, with no extranodal extension
  • N2c: The metastases occupy bilateral or contralateral lymph nodes, with none exceeding 6 cm in the greatest dimension and with no extranodal extension present
  • N3a: The metastasis occupies a lymph node and is over 6 cm in the greatest dimension, and no extranodal extension is present
  • N3b: Metastasis is present in any node(s), and clinically overt extranodal extension exists

Stage groupings, also defined by the AJCC, are delineated in the table below.

Table. (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

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