View larger version (89K): [in this window] [in a new window]   Figure 2. Removable maxillary partial denture with the clear the torus.plastic stent in place.

The patient had a complex medical history, but her medical conditions were well-controlled at the time of the consultation. She was ambulatory, lived alone and was able to carry out her daily activities without limitation. She was being treated for cardiovascular disease, hypertension, mild anxiety, hypothyroidism, osteopenia and hypokalemia. The patient’s medications included atenolol (50 milligrams), zolpidem (10 mg), amlodipine (5 mg), clopidogrel (75 mg), aspirin (1 mg), levothyroxine (0.05 mg), fludrocortisone (0.1 mg), hydrochloro-thiazide (25 mg), fenofibrate (130 mg) and alendronate (70 mg weekly), and she also took a multi-vitamin. Previous significant surgeries included a coronary artery bypass graft. The patient denied having any allergies.

The results of the extraoral examination were completely normal. The oral medicine health care provider did not note any ocular or cutaneous lesions. The intraoral examination revealed a large lobulated torus extending from the premaxilla to the soft palatal aponeurosis in an anterior-posterior direction and from the vertical aspects of the alveolar ridges laterally. The middle of the torus was ulcerated (8 x 6 millimeters) to the right of the mid-line, and necrotic bone was clinically evident centrally.

Can you make the diagnosis?

1. minor salivary gland tumor
   
2. angiocentric T-cell lymphoma (midline lethal granuloma)
   
3. squamous cell carcinoma
   
4. fixed drug reaction
   
5. bisphosphonate-associated osteonecrosis
   

	THE DIAGNOSIS

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E. bisphosphonate-associated osteonecrosis Reports of bisphosphonate-associated osteonecrosis (BON) (also referred to as osteonecrosis of the jaws and osteochemonecrosis) of the jaw associated with the use of intravenous bisphosphonates were first published in 2003.¹ Intravenous bisphosphonates are used in patients with skeletal lesions resulting from multiple myeloma; breast, lung and other cancers; and Paget’s disease of bone. The majority of reported cases of BON have been reported after dental procedures such as tooth extractions. However, BON also appears to occur spontaneously in some patients taking these drugs.²

By 2005, the literature also contained reports of cases of BON in patients taking orally administered nitrogen-containing bisphosphonates, which are used for the treatment of osteoporosis.³ For alendronate (the most commonly prescribed oral bisphosphonate), a BON incidence of approximately 0.7 cases per 100,000 person-years of exposure has been estimated.⁴ To date, a true cause-and-effect relationship has not been established.⁵ Migliorati and colleagues⁶ published a model for the pathogenesis of BON. Although there are no definitive diagnostic criteria or known risk factors, BON has been defined as the unexpected appearance of necrotic bone anywhere in the oral cavity of a patient receiving bisphosphonate treatment who has not received radiation therapy to the head and neck region. The necrotic bone persists for at least six to eight weeks in spite of standard therapy.⁶ Guidelines have been published to assist the clinician in the prevention and treatment of BON.^5,7,8

In this case, the oral medicine health care provider carefully considered the fact that the lesion had not healed during a four-month period in a patient with an essentially uncompromised immune system. This patient had been receiving alendronate therapy weekly for seven years. The dentists involved in her treatment (M.F., M.A.S.) did not remove any sequestrum. However, the oral medicine health care provider considered the patient’s history of having had a self-resolving sharp area of bone to be consistent with the presence of a small nidus of necrotic bone.

	DIFFERENTIAL DIAGNOSIS

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The midline of the hard palate is an uncommon site for a fixed drug reaction. On palpation, a salivary gland tumor does not have the bony hard consistency of a torus, but it appears firm or soft. The soft-tissue margins of the palate were not rolled or indurated, signs that might have suggested neoplastic disease such as a squamous cell carcinoma or a malignant minor salivary gland tumor. Angiocentric T-cell lymphoma (midline lethal granuloma) results in the destruction of the midline structures of the palate and nasal cavity; the lesion in this case exposed only palatal bone.

The oral medicine health care provider rendered a presumptive diagnosis of BON. The physician of record discontinued the patient’s alendronate therapy, as she did not have osteoporosis and was being treated prophylactically only for osteopenia. The physician of record felt that the alendronate therapy was not essential to her medical management. During the six-week healing period, the patient did not receive any bisphosphonate therapy. The bisphosphonate therapy was not discontinued for the purpose of treating the palatal lesion. The clinicians agreed that if the patient’s bone density decreased progressively into clinical osteoporosis, the physician of record would reinstitute the alendronate therapy. The oral medicine health care provider instructed the patient to take clindamycin (150 mg) four times daily for two weeks and apply topical chlorhexidine gluconate (0.12 percent) twice daily directly onto the ulceration using a cotton swab.

After two weeks, the lesion had begun to heal, but the patient was complaining of gastrointestinal distress related to the systemic antibiotic. For the following four weeks, until the lesion healed completely, the patient applied topical metronidazole 1.0 percent gel to the lesion twice daily. The oral medicine health care provider also instructed her to use the clear plastic stent until the lesion had resolved (Figures 3 and 4).

View larger version (96K): [in this window] [in a new window]   Figure 3. Palatal stent in place over the affected site.

View larger version (98K): [in this window] [in a new window]   Figure 4. Six-week follow-up showing re-epithelialization.

	CONCLUSION

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