Ameloblastoma

Dr. Indu K
Jun 21, 2024 3 min read
Ameloblastoma

An ameloblastoma is a rare odontogenic tumour, meaning it originates from the tissues responsible for the formation of the teeth. They are typically slow-growing lesions that have a high recurrence rate and the potential to spread to other parts of the body (e.g., lungs).

Causes of Ameloblastoma

  • The exact cause of ameloblastoma remains largely unknown due to its rarity, making it challenging to pinpoint specific factors from the limited reported cases.
  • Recent research has highlighted a potential association between mutations in certain genes, particularly BRAF and SMO, which regulate cell growth, division, and survival. These mutations have been observed in over 80% of ameloblastoma cases, prompting an ongoing investigation into their role.
  • Overexpression of TNFalpha, Matrix metalloproteinases (MMP), vascular endothelial growth factor, and Rank Ligand osteoclasts (bone destroying cells) have been identified in ameloblastomas, further contributing to our understanding of the tumour's development.

Types of Ameloblastoma

According to the latest World Health Organization (WHO) Classification of Head and Neck Tumours, ameloblastomas are classified into four different types:

  • Conventional ameloblastoma: This is the most common type and tends to grow, often found in the lower jawbone. Approximately 10% of cases recur after treatment.
  • Unicystic ameloblastoma: Less aggressive than the conventional type, it typically occurs at a younger age and is commonly located at the back of the lower jawbone near the molars. Recurrence can occur post-treatment.
  • Peripheral ameloblastoma: A rare type affecting the gums and oral tissues in the upper or lower jaw. It carries a low risk of recurrence after treatment.
  • Metastasising ameloblastoma: Extremely rare, characterised by tumour cells spreading away from the primary site in the jawbone.

Signs and Symptoms of Ameloblastoma

  • Ameloblastomas typically manifest as a slow-growing, painless swelling in the jaw region, with the mandible (lower jawbone) being the most common site.
  • While most cases occur in the third molar region of the mandible, they can also develop in the maxilla (upper jawbone).
  • Due to their aggressive nature, ameloblastomas can lead to facial disfigurement, dental misalignment, and tooth loosening as they grow.
  • In some instances, neighbouring tissues like the sinuses and eye sockets may become involved.
  • Although pain is not a characteristic symptom, it can occur if there is bleeding within the tumour or surrounding tissues.

Diagnosis

  • Diagnosis involves a combination of imaging techniques such as dental X-rays (orthopantomogram), CT scans, and MRIs to assess the extent of bone and soft tissue involvement.
  • Radiological findings may show lytic lesions with scalloped margins for unicystic ameloblastomas or a characteristic "soap bubble" appearance for conventional or multicystic types.
  • Definitive diagnosis is confirmed through a biopsy of the lesion, which helps rule out other bone disorders and confirm the presence of ameloblastoma.
  • In cases of suspected metastasising ameloblastoma, a PET scan may be conducted to detect distant metastasis sites.

Treatment

  • Treatment typically involves radical maxillofacial surgery, where a portion of the affected jawbone is removed along with the tumour in a complete "en bloc" resection.
  • Reconstruction of the jaw may be necessary post-surgery to address any functional impairments.
  • Chemotherapy may be considered in cases of metastasising ameloblastoma, often in combination with surgical intervention.
  • Targeted molecular therapies like dabrafenib or vemurafenib may be utilised for ameloblastomas positive for the BRAF V600 mutation.
  • Prognosis depends on various factors, including age, tumour location, size, and stage of disease, with untreated cases posing risks of severe facial disfigurement and airway compromise.

Final Words

Ameloblastoma is a rare but potentially serious condition that requires timely diagnosis and appropriate treatment. It is an important topic in dentistry and in many competitive exams like the Australian Dental Council (ADC) Exam. 

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Dr. Indu K
Dr. Indu K
about the author

Dr. Indu K is a dentist with one year of clinical experience. She seamlessly transitioned into content writing three years ago. Her passion lies in making complex medical information accessible to everyone. She uses her unique blend of medical knowledge and exceptional writing skills to bridge the gap between healthcare and the general audience.