bubble_chart Overview

Ameloblastoma is a central epithelial tumor of the jawbone and is relatively common among odontogenic tumors. There are differing views regarding the tissue origin of ameloblastoma, but most believe it arises from the enamel organ or dental lamina epithelium. Macroscopically, ameloblastoma can appear as solid or cystic, or both components may coexist within the same tumor. Cystic variants may contain brownish fluid within the cystic cavities. Microscopically, tumor cells form varying-sized masses or cords dispersed within the connective tissue stroma. According to the World Health Organization and commonly used domestic classifications, ameloblastoma is typically divided into five types: follicular, plexiform, granular cell, squamous metaplastic, and basal cell.

bubble_chart Clinical Manifestations

1. Jaw swelling and facial deformity: The mandible is more commonly affected than the maxilla, with a predilection for the molar region and mandibular angle. Growth is slow, and the initial stage [first stage] is asymptomatic. Jaw swelling and deformation are often the chief complaints when patients seek medical attention.
2. When the tumor involves the alveolar bone, it can cause tooth loosening, resorption, and displacement.
3. Numbness or discomfort in the lower lip: This symptom occurs when the tumor compresses the inferior alveolar nerve or undergoes malignant transformation (which is extremely rare).
4. Extensive bone destruction may lead to pathological fractures.
5. Ameloblastoma of the maxilla can extend into the maxillary sinus, nasal cavity, and orbit, resulting in corresponding symptoms such as stuffy nose, upward displacement of the orbit, and obstruction of the nasolacrimal duct.

bubble_chart Auxiliary Examination

1. For patients with typical clinical manifestations and relatively clear preoperative diagnosis, the examination items are mainly based on the "A" examination frame limit;
2. For patients with atypical clinical manifestations, difficult differential diagnosis, and large tumors requiring complex surgery, the examination may include the "B" examination frame limit.

bubble_chart Diagnosis

1. Painless progressive enlargement of the jawbone, which can lead to facial deformity, often without specific subjective symptoms.
2. Malocclusion, tooth displacement, loosening or loss, occasionally pathological fracture.
3. Jawbone swelling with a nodular, uneven surface, sometimes accompanied by a table-tennis-ball-like elastic sensation upon pressure.
4. X-ray imaging shows jawbone swelling with irregular multilocular cystic radiolucent areas. The margins of these areas are not smooth and may exhibit crescent-shaped notches. The loculations vary greatly in size. When the alveolar bone is involved, a distinct "apical infiltration sign" may be observed—irregular destruction and absorption of the alveolar bone around the tooth root apex, with the root appearing jagged or truncated.
5. If rapid growth is accompanied by symptoms such as pain or ulceration, and X-ray shows destruction and disappearance of bony septa with a mottled appearance, malignant transformation should be suspected.
6. Aspiration of cystic fluid often yields a brownish liquid, sometimes containing cholesterol crystals but no keratinized epithelium.
7. Diagnosis is confirmed by histopathological examination.

bubble_chart Treatment Measures

Surgical treatment should follow the principles of managing borderline tumors, which involves resecting the entire tumor with a margin of approximately 0.5 cm beyond the tumor. For smaller mandibular tumors, a block resection of the mandible can be performed, while larger mandibular tumors require en bloc resection. The resulting tissue defect can be immediately repaired with bone grafting.

For general surgical prophylaxis, sulfonamides (such as compound formula co-trimoxazole) or drugs primarily effective against Gram-positive bacteria (such as erythromycin or penicillin) are typically used. For more extensive surgeries involving bone grafting or complex reconstructions, combination therapy is generally employed, commonly consisting of "drugs effective against Gram-positive bacteria (e.g., penicillin) + drugs effective against Gram-negative bacteria (e.g., gentamicin) + drugs effective against anaerobic bacteria (e.g., metronidazole)." In cases of severe pre- or post-operative infection or large, complex surgical wounds, effective antibiotics can be selected based on clinical evaluation and drug sensitivity testing.

Ameloblastoma of the jaw is a benign tumor. However, due to its locally invasive growth characteristics and the potential for rare malignant transformation when the tumor persists for an extended period or is inadequately managed, it is classified as a borderline tumor (i.e., a tumor intermediate between malignant and benign neoplasms). Therefore, once diagnosed, surgical treatment should be initiated as early as possible, as the tumor gradually enlarges over time, leading to greater tissue loss and functional impairment. If occurring in the maxilla, it may invade the skull base, making complete surgical resection difficult. With timely and appropriate surgical intervention, the prognosis is favorable. Postoperative tissue defects can be reconstructed using autologous bone grafts or bone substitutes. Defects following maxillectomy can be restored in shape and masticatory function with prosthetic devices, while mandibular defects repaired with autologous bone grafts can also regain masticatory function through dental implant techniques.

bubble_chart Cure Criteria

1. Cure: Pathological examination confirms the tumor was resected within the normal range of the jawbone, and the jawbone defect was immediately repaired with bone grafting or substitute implantation, restoring normal appearance. If immediate bone grafting was not performed after tumor resection or the grafting failed due to infection, the infection was controlled through treatment, and function was restored satisfactorily.
2. Improvement: Recurrent large tumors (e.g., near the skull base) were mostly resected.
3. Not cured: Postoperative pathological examination confirmed the tumor was not completely resected, requiring another surgery.