What is Ameloblastoma?

Ameloblastoma is an uncommon, benign and aggressive tumour that grows most frequently in the mandible (jaw) close to the molars. Ameloblastoma starts in the cells that shape the defensive lacquer (the enamel lining) covering the teeth. Prevalence of ameloblastoma is higher in men than in women, and although it can be diagnosed at any age it is frequently diagnosed in people between the ages of 40 and 50. Although benign it can be also very aggressive, growing into the jawbone and causing significant swelling, discomfort and pain. In rare circumstances, ameloblastoma cells can spread to different parts of the body such as the lymph nodes in the neck and into the lungs.

Ameloblastoma is the most well-known kind of odontogenic lesion (cysts or tumours that develop in the jawbone or the soft tissues of the mouth), and it is the second most common odontogenic lesion in terms of prevalence globally.

Clinically, ameloblastomas are classified in four separate categories (1):

• Unicystic
• Solid or multicystic
• Peripheral
• Malignant

Management and treatment of Ameloblastoma

There are a number of different treatment options available for ameloblastoma that depend on a number of clinical and patient factors. The size of the tumour, the location site of the tumour, and the type and appearance of the cells involved are the usual clinical factors that are considered in deciding an appropriate course of action.

Tumour surgery

An often used treatment option is tumour surgery, in which the goal is to remove the tumour from the mandible completely and a small margin of healthy tissue that surrounds it.

Because ameloblastoma often grows into the jawbone, it requires the specialist attention of a maxillofacial surgeon who is able to remove the affected portion of the bone.

Surgery that is particularly aggressive and removes a large amount of the bone is often considered in order to reduce the risk of reoccurrence. 

Surgery to remove the tumour will also often result in the need for surgery to repair the jaw. This is performed by reconstructive or plastic surgeons who will work to improve the appearance of the jaw and restore eating and speaking functions.

Malignant development of Ameloblastoma

Although ameloblastoma are generally benign and noncancerous, it has a high percentage of local recurrence and possible malignant development if it is initially treated inadequately. In this case, other treatments can be considered such as radiation therapy or chemotherapy. However, a recent study that profiled over 3500 patients who had ameloblastoma suggested that chemotherapy and radiotherapy was contraindicated for a large number of the study group (2).

The most common treatment option is surgical removal, with radiation therapy used when this option is not available for clinical reasons or patient choice. Whichever treatment options patients pursue, they often require the ongoing support of a range of healthcare professionals who provide supportive therapy to help them regain the functions of the jaw pre-surgery. 

These might include: 

• Speech therapists
• Physical therapists
• Prosthodontists who make replacements for missing teeth or the natural structures of the mouth that have been damaged or altered during surgery

Long-term outcomes and risks

There is a high risk of ameloblastoma reoccurring in patients who have already had the condition. This is the main rational for treating the condition aggressively and surgically, as more than 50% of cases reoccur within 5 years postoperatively and ameloblastomas left untreated can become very large, destructive and multilocular (consisting of many small parts or cavities) (3).

Many studies reinforce the current professional opinion that aggressive surgery is a more appropriate treatment option than conservative surgery: A  clinical review of 20 individual surgeries, conducted by a group of maxillofacial consultants in the national Journal of Maxillofacial Surgery, concluded that aggressive surgery reduced the chance of tumour recurrence and was the most appropriate option in conjunction with defect repair that ensures the patient had both a good functional and aesthetic outcome (4). The study also highlighted high levels of recurrence in patients treated conservatively, with 60% of patients experiencing a returning ameloblastoma.

Complications

As with all surgeries, there are some risks of complications attached to the procedure. The most commonly documented complications include:

• An increasingly nasal tone of speech (as a result of defects in the maxillary region)
• Cosmetic deformity
• Fluid leak into the nasal activity and difficulty chewing (impaired masticatory function) (5)

However, many surgeries are completed without incident and success rates for surgical intervention are generally high.

Further surgery

Occasionally, patients will have to undergo more than one surgery to prevent the impairment of speech and swallowing, as well as for bone grafts that often take place for cosmetic reasons.

Postoperative

It is well acknowledged in the literature that the postoperative period is as important as the surgery itself – as such, it is generally recommended that patients continue to see an appropriate healthcare professional twice a year following surgery for clinical and radiological examination for a period of up to five years (6). Some healthcare professionals extend beyond this, continuing to review their patients annually up to 10 years afterwards to avoid recurrence.

References

1. Mehlisch DR, Dahlin DC, Masson JK (1972) Ameloblastoma: A clinicopathologic report. J Oral Surg 30:9–22
2. Reichart PA, Phillipsen SE, Sonner S (1995) Ameloblastoma: biological profile of 3677 cases Eur J Cancer B Oral Oncol 31B(2):86-99
3. Rosenstein T, Pogrel MA, Smith RA, Regezi JA (2001) Cystic ameloblastoma: behaviour and treatment of 21 cases J Oral Maxillofac Surg 59(11):1311-6
4. Dandriyal R, Gupta A, Pant S, Baweja HH (2011) Surgical management of ameloblastoma: Conservative or radical approach? J Oral Maxillofac Surg 2(1)22-27
5. Zemann W, Feichtinger M, Kowatsch E, Karcher H (2007) Extensive ameloblastoma of the jaws: surgical management and immediate reconstruction using microvascular flaps Oral Surg Oral Med Oral Pathol Oral Radiol Endod 103(2):190-6
6. Becelli R, CArboni A, Cerulli G et al (2002) Mandibular Ameloblastoma: Analysis of Surgical Treatment Carried Out in 60 Patients Between 1977 and 1988 J Cranofacial Surg 13(3)395-400