Ameloblastoma is a benign odontogenic tumor of maxillofacial localization that causes destruction of bone tissue. As ameloblastoma develops, facial asymmetry occurs, there is a gradual deformation of the jaw, loosening and displacement of the dentition, violation of the chewing function. Ameloblastoma is diagnosed on the basis of anamnesis, symptoms detected during examination and necessary studies: radiography, computed tomography, cytological analysis, etc. Treatment of the disease is carried out exclusively surgically and consists in resection of the affected area of the jaw bone or exarticulation of the jaw.
ICD 10
D16.5 Benign neoplasm of bones and articular cartilage (lower jaw bone part)
Meaning
Ameloblastoma is the most common form of odontogenic tumor that occurs in the practice of surgical dentistry. In more than 80% of cases, ameloblastoma occurs in the lower jaw, the upper jaw is affected less often. It occurs with the same frequency in men and women, usually at the age of 20-60 years. It is possible to develop ameloblastoma in children and adolescents – this disease accounts for 6-7% of all benign formations of dental localization in childhood.
According to statistics, in a significant part of patients, ameloblastoma is detected at relatively early stages (1-6 months), which is very important for successful treatment. Ameloblastoma is often detected after radiography for another dental disease, although there are also late visits to the doctor (with the duration of the disease from 1 year to several years), when the tumor has already developed in a significant area. Ameloblastoma often recurs, and with an unfavorable course and neglect of the disease, malignancy of a benign formation is possible.
Causes
Currently, there are several hypotheses about the causes of the development of this tumor. Some scientists suggest a connection between the disease and the pathology of the development of the dental rudiment, others believe that ameloblastoma arises from odontogenic epithelial residues (the so-called Malasse islets). Be that as it may, the exact causes of the pathology have not yet been established.
Classification
Clinically, there are two forms of the disease – cystic and solid (massive). Cystic ameloblastoma is the most common, it is characterized by the presence of isolated or partially connected cysts, which are lined from the inside with a thin epithelial membrane. The difference between massive ameloblastoma is the presence of spongy tissue and sometimes radiologically undetectable cysts of various sizes, which, with prolonged development of pathology, gradually merge into one or more large cavities.
Microscopically, there are several types of tumors: follicular, pleomorphic, acanthomatous, basal cell and granular cell. The first two types of ameloblastoma are most common, but often different types of histological structure can be found within the same tumor.
- Follicular form is characterized by the presence of individual islands (follicles) of epithelial cells, which are located in the stroma of connective tissue.
- Pleomorphic form is an extensive network of odontogenic epithelial strands.
- With acanthomatous ameloblastoma, pronounced squamous metaplasia with the formation of keratin inside the areas of tumor cells is observed.
- Basal cell ameloblastoma is very similar to basal cell carcinoma.
- The granular-cellular form is characterized by a high content of acidophilic granules in the epithelium.
Ameloblastoma is characterized by the presence of two types of cells: stellate and cylindrical. The latter are important in relapses of the disease, since they have long epithelial processes extending into healthy tissue beyond the boundaries of the tumor.
Symptoms
The development of ameloblastoma is very slow, and the patient may not notice any symptoms for a long time. However, with the progression of the disease, the jaw is deformed. The first visible manifestation of the disease is a violation of the symmetry of the face, swelling on the part of the lesion. It should be noted that the degree of asymmetry may vary: from small to significantly pronounced. Ameloblastoma of the upper jaw is much less common, but it can occur even more imperceptibly visually, since the tumor spreads into the maxillary sinus.
When the tumor begins to damage the structure of bone tissue, the patient has pain, which he can take for dental. Loosening and displacement of teeth occurs. The jaw at the site of the lesion is gradually deformed, and with the further progression of the pathology, the cortical plate becomes thinner – a characteristic parchment crunch appears. During palpation, a smooth or bumpy fusiformly swollen area of the bone is determined, with thinning, the bone tissue easily bends and springs. From the side of the oral cavity, deformation of the alveolar process can be observed.
The skin over the affected area remains unchanged for a long time, mobile, easily gathered into a fold. With the development of ameloblastoma in the upper jaw, the alveolar process and the hard palate are deformed, there is a high probability of the tumor spreading into the nasal cavity and eye socket.
Complications
The course of the disease can be complicated by inflammatory processes – often fistulas with serous-purulent secretions are found in the oral cavity. With unfavorable development or prolonged incorrect treatment, tumor malignancy is possible, this occurs in about 4% of cases.
Diagnostics
Ameloblastoma is diagnosed by a maxillofacial surgeon based on anamnesis, clinical manifestations and data obtained during the examination: radiography, computed tomography, cytological examination, etc.:
- X-ray. Radiographic examination is of great importance in the diagnosis: orthopantomography, axial (axial) radiography, a picture in a lateral projection and radiography of the alveolar process “in the bite” if necessary. Radiographs of the affected area in various projections allow us to accurately determine the degree and size of the formation, the structure of the focus, the boundaries of the tumor, the state of the cortical plate, etc.
- Cytology. The most informative for the accurate diagnosis of ameloblastoma is the cytological examination of the punctate of education. The analysis reveals fatty-granular cells, shaped blood elements, squamous epithelial cells, fibrous fibrin, stellate cells and cholesterol crystals. This study allows you to accurately confirm the presence of a benign tumor.
Ameloblastoma is differentiated from dental cysts of inflammatory etiology, cystadenoid carcinoma of the salivary gland and squamous cell carcinoma.
Treatment
Treatment of the disease consists in surgical removal of the tumor-affected area of the jaw within healthy tissues. The volume of bone resection depends on the size, localization and neglect of the pathology.
Currently, there are rare cases when ameloblastoma reaches large sizes, most often it is detected in the early stages. With early diagnosis of a tumor, modern surgical methods allow it to be removed without resection or partial exarticulation of the jaw. Such operations do not disrupt the continuity of the jaw, often allow you to preserve its functions and avoid disfiguring the patient’s face. To prevent the development of relapse of the disease, the walls of the postoperative cavity are treated with a concentrated solution of phenol so that the epithelial elements of ameloblastoma undergo necrosis.
In case of significant tumor development, the jaw is resected or partially exarticulated (with a violation of continuity). With ameloblastoma complicated by suppuration, simultaneous surgical elimination of the inflammatory process and removal of the tumor is performed. Before surgery, the oral cavity must be sanitized. The operation itself is performed under general or local anesthesia.
Postoperative complex treatment always includes antibacterial, symptomatic and corrective therapy. The diet after the removal of the tumor should not contain coarse and hard foods, after eating it is necessary to rinse the postoperative cavity. In case of loss of a significant amount of bone tissue by the patient, bone grafting is used to restore the function of the jaw and orthopedic structures are made. In addition, when a person is disfigured due to surgery, the social aspect of the patient’s rehabilitation is of great importance, in which a psychologist can take part.
Prognosis and prevention
Early diagnosis of the disease is of great importance for the successful treatment of ameloblastoma with the least consequences. In case of timely detection and proper surgical treatment of ameloblastoma, the prognosis is encouraging. In order to avoid severe consequences and irreparable loss of bone tissue, it is necessary to consult a dentist and undergo an examination at the first suspicious symptoms. In addition, to ensure early diagnosis of ameloblastoma, it is recommended to visit a doctor regularly (once every six months) for a preventive examination.
Literature
- Gaillard F., Jones J. Ameloblastoma // Radiopaedia. — 2021.
- Masthan K. M. K., Anitha N., Krupaa J., Manikkam S. Ameloblastoma // J Pharm Bioallied Sci. — 2015. — Р. S167–S170. link
- Dandriyal R., Gupta A., Pant S., Baweja H. H. Surgical management of ameloblastoma: Conservative or radical approach // Natl J Maxillofac Surg. — 2011. — № 1. — Р. 22–27. link
- Lee S. K., Kim Y. S. Current concepts and occurrence of epithelial odontogenic tumors: I. Ameloblastoma and adenomatoid odontogenic tumor // Korean J Pathol. — 2013. — № 3. — Р. 191–202.