Pathologic fracture of the mandible caused by metastatic follicular thyroid carcinoma. JCDA 2009;75:457-60.

(1)

口腔病理科 On-Line KMU Student Bulletin

- 1 -

原文題目(出處)： Pathologic fracture of the mandible caused by metastatic follicular thyroid carcinoma. JCDA 2009;75:457-60.

原文作者姓名： AlGahtani M, Alqudah M, AlShehri S, Binahmed A, Sandor GKB.

通訊作者學校： The Hospital for Sick Children, S-525, 555 University Ave, Toronto, Canada

報告者姓名(組別)： Intern B組廖珮伃

報告日期： 98.11.09

內文：

ABSTRACT

A pathologic fracture may be an acute event or a chronic long-standing

ill-defined problem, and the causes are numerous. The dental practitioner may be the first health care practitioner to see a patient with a pathologic fracture of the jaw. This case report is intended to inform dental practitioners about

pathologic fractures and the need for prompt referral to minimize patient suffering.

A pathologic fracture may occur when a bone has been weakened by an underlying pathologic process, even when it is subjected to otherwise normally tolerated loading forces

Although such fractures may occur in any bone, their most common location in the orofacial skeleton is the mandible.

Weakening of the jaw may be congenital or acquired.

The purpose of this case report is to describe the presentation of a pathologic fracture of the mandible and review the features and

(2)

- 2 -

management of pathologic fractures that dentists may encounter.

CASE REPORT Age：66 y/o Gender：Female

C.C.：A 4-month history of swelling in her left cheek.

P.I.：The patient had noticed a clicking in her left mandible when she moved her jaw and a deviation of the chin to the right side. She also reported

numbness of the lower lip and difficulty chewing.

Clinical examination：a hard，tender，fixed swelling of the left mandible extending from the ramus to the submandibular area and completely

obliterating the mandibular anatomy. Significant expansion of the left mandible in the buccolingual direction and unusual mobility of the mandible when

pressure was applied to the ramus. A palpable left thyroid nodule was present, but no lymphadenopathy was found.

Radiologic investigation (orthopantomogram)：a destructive radiolucent lesion on the mandible, extending from the left first premolar anteriorly to the ramus and a pathologic fracture of the mandible.

Incisional biopsy：Tissue from the left mandible contained thyroid follicles lined with cuboidal cells with round to oval nuclei and moderate amounts of

cytoplasm. Most of the follicles contained intraluminal colloid, which was thyroglobulin (DAK-Tg6) positive.

Metastatic work‐up：computed tomography of the head and neck, which showed a large destructive lesion in the left mandible associated with a large soft tissue mass measuring 4.6 × 4.2 × 4 cm. Injection of contrast dye greatly enhanced the image and indicated a hypervascular lesion.

Multiple small lymph nodes were present in the neck. A large

heterogeneous mass (3.4 ×4.7 cm) involving the left lobe of the thyroid gland had caused displacement of the trachea.

Recommended treatment：total thyroidectomy, lateral neck dissection and resection of the mandibular lesion.

(3)

- 3 -

A segmental mandibulectomy was performed and a 2.7-mm reconstruction plate was used to span the gap after resection and provide the rigidity needed to allow the patient mandibular mobility and function without pain.

DISCUSSION

Pathologic fractures of the jaw may lead to severe pain and suffering, inability to eat and difficulty in swallowing.

Symptomatic pathologic fractures require active treatment to re-establish the rigidity of the jaw and permit pain-free movement and mastication.

Patients with suspected pathologic fractures of the jaw should be examined clinically and radiographically, then referred for prompt evaluation by specialists, such as oral and maxillofacial surgeons.

Follicular carcinoma of the thyroid accounts for 17% of all thyroid

malignancies. It is most common in women between the ages of 22 and 50 years.

The presenting symptom is a long-lasting neck lump that may be noted by the dental practitioner during head and neck examination.

Follicular thyroid carcinoma metastasizes through the hematologic route to the lungs, bone, liver and brain. Lymphatic spread occurs rarely. In this case, a metastatic follicular carcinoma of the thyroid was an unusual cause of a pathologic fracture of the mandible.

(4)

- 4 -

The true incidence of metastatic tumors in the bones of the jaw is unknown.

Involvement of the jaw in metastasis appears to be less common than that of other bones, as the amount of red bone marrow and blood vessels in the jaw bones tends to decrease with age.

Most (60%–80%) metastasis involving jaw bones occurs in the mandible, mainly in the molar and premolar areas, when compared to other bones of the facial skeleton. This is thought to be due to the greater presence of hematopoietic tissue in the mandible. Because the mode of metastasis is hematogenous, the neoplastic cells become deposited in areas where there is vascular tissue.

Metastatic tumours are most common in the fifth to seventh decades of life. The most common origins of metastasis vary with gender: breast, ovary and thyroid in female patients and lung, prostate, kidney and liver in men.

The lung is the most common origin of metastasis into oral soft tissues, whereas the breast is the most common origin of metastatic tumours in the jaw bones.

Metastatic tumours in the jaw present with pain, swelling, mobility of teeth, delay in healing of extraction sockets, pathologic fractures or paresthesia.

Radiographically, metastatic lesions are most often ill-defined and are usually osteolytic or radiolucent, although they may be osteoblastic, radiopaque mixed lesions.

The lack of large numbers of patients with mandibular metastasis prevents accurate determination of the prognosis associated with the treatment described above.

Some evidence indicates that resection of solitary bony metastasis, along with total thyroidectomy, may increase survival among those with follicular thyroid carcinoma.

Treatment of the pathologic fracture in the case described in this report rendered the patient symptom-free and restored her quality of life to the prefracture level.

題號題目

1 Most (60%–80%) metastasis involving jaw bones occurs in the mandible；then whereis the next common site?

(A) Ant. Hard palate (B) Maxillary sinus (C) Mandibular condyle (D) Root apex

答案(B) 出處：Oral Radiology Principles and Interpretation p.467

題號題目

2 Which is not clinical features of metastatic disease?

(A) Dental pain

(B) Numbness of the 1^st branch of trigeminal nerve.

(C) Hemorrhage from the tumor site (D) Pathologic fracture of the jaw

答案(B) 出處：Oral Radiology Principles and Interpretation p.467