eMedicine Specialties > Dermatology > Diseases of the Oral Mucosa

Metastatic Neoplasms to the Oral Cavity: Differential Diagnoses & Workup

Author: Abraham Hirshberg, MD, DMD, Senior Lecturer, Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel Aviv University, Israel
Coauthor(s): Amos Buchner, DMD, MSD, Chairman, Professor, Department of Oral Pathology and Oral Medicine, Tel Aviv University School of Dental Medicine, Israel
Contributor Information and Disclosures

Updated: Mar 28, 2008

Differential Diagnoses

Other Problems to Be Considered

Oral soft tissues
Pyogenic granuloma
Peripheral giant cell granuloma (only in the gingiva)
Fibrous epulis (only in the gingiva)
Malignant primary tumor (oral cancer, including salivary gland tumor)

Jawbone (differential diagnosis depends on location)
Malignant tumors (eg, primary intraosseous carcinoma, other malignant odontogenic tumors)
Central malignant salivary gland tumors
Sarcoma (eg, malignant fibrous histiocytoma, fibrosarcoma)

Bony lesion can mimic benign lesion (some cases)
Periapical pathology
Infected odontogenic cyst or tumor
Osteomyelitis

Workup

Imaging Studies

• The balance between the activities of osteoblasts and osteoclasts in general determines the phenotype of metastatic bone lesions, either osteolytic or osteoblastic. Metastases from prostate cancer nearly always form osteoblastic lesions in bone⁷ ; by contrast, bone metastases from kidney, lung, or breast cancers are more often osteolytic.
  • The most common radiographic presentation is that of a lytic lesion with ill-defined margins.
  • Occasional osteoblastic lesions are observed.
  • In approximately 5% of the patients, the radiographs do not reveal any pathologic changes.
• An oral radiography survey may be helpful.
• Periapical and panoramic radiographs, CT scans, and MRIs can be obtained to evaluate the extent of the lesion.
• Lack of radiographic changes does not exclude the possible presence of a small metastatic deposit in the jawbone.

Procedures

• The following steps constitute the diagnostic algorithm for evaluation of oral metastases:
  • Review the clinical history.
  • Review the available radiographic findings.
  • If a history of a previous tumor exists, obtain the slides and reports for review.
  • Perform a biopsy of the lesion.
  • Evaluate the light microscopic features of the neoplasm. On the basis of the histologic features, determine the need for special studies (eg, histochemical staining, immunohistochemical tests, electron microscopy).
  • In cases in which the primary tumor is not found (unknown primary), look for signs and symptoms in an attempt to identify the potential primary. This can be accomplished with a complete history and physical examination, with special attention to the breast, rectal, and pelvic examination findings.
    • The standard battery of laboratory tests includes a complete blood cell count, liver function tests, calcium level, urinalysis, and serum creatinine value. A chest radiograph is also always indicated. Chest radiographs and chest CT scans have proven to be useful in the detection of primary lung tumors.
    • Sex-specific tests include serum prostate-specific antigen assay and transrectal ultrasound for male patients and mammography and cervical Papanicolaou test (Pap smear) for female patients.
    • Additionally, a CT scan of the abdomen and pelvis has been used in some series; it has been shown to identify the primary tumor in 10-35% of patients. A CT scan can identify primary tumors in the pancreas, liver, adrenals, kidney, gallbladder, ovaries, and stomach.
    • Positron electron transmission scanning with fluorodeoxyglucose is rapidly gaining favor in the evaluation of unknown primary cancers, particularly in instances in which other image modalities have failed to identify a source.
  • Plan the treatment protocol based on the clinical, pathological, and radiographic information.

Histologic Findings

The diagnosis is always based on histologic findings in the biopsy specimen. The clue to the diagnosis is the resemblance of the metastasis to the primary tumor. If a history of a previous tumor exists, compare the current histologic findings with those of the preexisting primary malignant tumor. In some cases, histochemical staining, immunohistochemical tests, and electron microscopy should be performed to identify the primary source of the metastatic tumor.

Attend to the differentiation of the primary intraoral malignancies from metastatic tumors. Several primary intraoral malignancies (especially those originating from salivary glands) have histologic features similar to those of tumors in distant organs: for example, primary ductal carcinoma of a salivary gland origin versus metastatic breast carcinoma, primary intraoral clear cell carcinoma versus metastatic renal cell carcinoma, primary intraoral squamous cell carcinoma versus metastatic squamous cell carcinoma from the lung, or primary intraoral malignant melanoma versus metastatic malignant melanoma. Malignant soft tissue tumors may originate intraorally, but, because of their rarity, one should always consider a metastatic origin.

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