Fibromatosis (Desmoid Tumor)
Etiology: Fibromatosis has no known etiology, but they are considered uncommon and locally invasive tumors. There is no specific etiology associated with most of these types of neoplasms. They may be associated with mutation of the cell’s DNA or disruption of another defense mechanism against uncontrolled growth of cells. At one time, they were thought to be reactive lesions, because they occasionally appeared at a site where a previous surgical procedure was performed.
Method of Transmission: Several forms of fibromatosis (myofibromatosis, familial adenomatous polyposis, and multicentric fibromatosis) are considered inherited conditions.
Characteristics: Fibromatosis manifests as a slowly enlarging soft tissue mass when observed in the oral cavity. Facial asymmetry can be expected as the lesions enlarge. The soft tissues surrounding the mandible are commonly affected. If the bone of the mandible is affected, the lesions appear as ill-defined radiolucencies. Expansion of the cortical bone may occur.
Dental Implications: Early diagnosis of any enlarging mass is crucial to obtaining a favorable treatment outcome. The dental hygienist is in an excellent position to provide thorough examinations, which can identify abnormal growths when they are small.
Treatment and Prognosis: The treatment of choice is aggressive surgical excision with wide margins, anti-inflammatory medications, chemotherapy, and radiation therapy, and other forms of local therapy are suggested. Because there is a high rate of recurrence with these tumors, monitoring of the patient is paramount. The tumors have been known to regress spontaneously, and sometimes, they may be watched for a period of time, but, in general, they have a reported recurrence rate of approximately 30% for very aggressive lesions in the head and neck area. Deaths have been reported due to recurrence and locally aggressive invasion of vital tissues. There is no metastasis.
Fibrosarcoma
Etiology: The development of fibrosarcoma may be linked to previous radiation therapy and tissue trauma such as a burn injury.
Method of Transmission: Not applicable
Characteristics: The most common extraoral presentation of fibrosarcoma is in the thigh bone around the knee joint.
Dental Implications: Early identification of enlarging soft tissue masses is of utmost importance in obtaining a favorable treatment outcome.
Treatment and Prognosis: The treatment of choice is surgical excision with wide margins. The prognosis is guarded. There is local recurrence in 50 to 75% of cases, and this is the most common cause of death. Distant metastasis occurs in 20 to 40% of cases, with spread occurring more commonly to the lungs. The 5-year survival rate is 50 to 70%.
Neurilemmoma (Schwannoma
)Etiology: The neurilemmoma arises from proliferation of the Schwann cells of the nerve sheath. They are considered benign neural neoplasms of Schwann cell origin.
Method of Transmission: Not applicable
Characteristics: Neurilemmomas usually appear as small, smooth-surfaced, firm, nodular growths in the head and neck area and on the flexor surfaces of the arms and legs. The lesions are normally painless unless they are very large or they impinge on vital tissues. Intraoral neurilemmomas manifest as smooth-surfaced submucosal masses The lesions can occur anywhere in the mouth but occur most frequently on the tongue. They can also occur within the bone of the maxilla or mandible, where they appear as well-defined radiolucencies. Bone lesions are often associated with pain and paresthesia (numbness).
Dental Implications: Accurate interpretation of radiographic findings in areas where a patient reports pain and/or paresthesia may be essential to detect this neoplasm, when it arises in bone.
Treatment and Prognosis: The treatment of choice is surgical excision. There is little chance of recurrence or with malignancy so the prognosis is excellent.
Neurofibroma
Etiology: The solitary neurofibroma is a benign neoplasm that originates from the Schwann cells and/or connective tissue cells that support the peripheral nerves. It is the most common type of peripheral nerve neoplasm. Neurofibromatosis (von Recklinghausen disease of the skin) is an inherited syndrome characterized by multiple neurofibromas and other abnormalities. The solitary form of neurofibroma and the form associated with the inherited syndrome display similar clinical and microscopic appearances. Neurofibromatosis is discussed later in this chapter with other genetic disorders.
Method of Transmission: Not applicable
Characteristics: Intraorally, the tumor manifests as a slow-growing, smooth-surfaced, asymptomatic mass. It is most commonly located on the tongue or buccal mucosa; however, it can be located at any intraoral site
Dental Implications: The presence of multiple neurofibromas may indicate a relatively common genetic disorder called neurofibromatosis. The dental hygienist may be in a unique position to detect these lesions and request referral of the patient for medical evaluation.
Treatment and Prognosis: Surgical excision is the preferred treatment. Solitary neurofibromas have little chance of recurrence and thus have an excellent prognosis.