13/04/2025
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Ameloblastoma – An Odontogenic Tumor
🔵 Definition:
Ameloblastoma is a benign but locally aggressive odontogenic tumor that originates from the odontogenic epithelium. It is believed to arise from the remnants of the dental lamina, enamel organ, the epithelial lining of an odontogenic cyst (particularly dentigerous cysts), or from the basal cells of the oral epithelium. It does not involve ectomesenchyme and does not form hard tissues like enamel or dentin.
🔵 Epidemiology:
Ameloblastomas account for approximately 10% of all odontogenic tumors. They commonly occur between the third and fifth decades of life, with a slight male predilection. The mandible is the most common site, particularly the molar–ramus area, accounting for over 80% of cases.
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🔵 Clinical Features:
Slow-growing but locally invasive
Typically asymptomatic in early stages
Later may present with facial swelling, bony expansion, loosening of teeth, or malocclusion
No pain unless secondarily infected
Large lesions may cause facial deformity
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🔵 Radiographic Features:
Multilocular radiolucency is the classic appearance (“soap bubble” or “honeycomb” pattern)
Occasionally appears as unilocular, especially in early stages or unicystic variants
Well-defined borders
May cause root resorption or cortical bone expansion and thinning
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🔵 Histopathology:
Ameloblastomas resemble the developing enamel organ histologically. Several patterns exist:
1. Follicular – The most common type, with islands of epithelium showing peripheral palisading columnar cells (resembling ameloblasts) and central stellate reticulum-like cells.
2. Plexiform – Long interconnecting strands of odontogenic epithelium in a loosely arranged stroma.
3. Acanthomatous, Granular cell, Basal cell, and Desmoplastic types – each with unique histologic variations.
The unicystic ameloblastoma appears as a cyst with mural proliferation of ameloblastic epithelium, often seen in younger patients.
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🔵 Types/Classifications:
According to the WHO 2022 Classification, ameloblastomas are categorized into:
1. Conventional/Multicystic Ameloblastoma
2. Unicystic Ameloblastoma
3. Peripheral (Extraosseous) Ameloblastoma
4. Metastasizing (Malignant) Ameloblastoma
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🔵 Treatment:
Despite its benign nature, ameloblastoma has a high recurrence rate if not treated appropriately.
Conservative treatment (curettage, enucleation) is associated with high recurrence.
Radical surgical resection with at least 1-1.5 cm margin is considered the gold standard, especially for conventional types.
Unicystic ameloblastomas, especially the luminal or intraluminal subtypes, may respond well to conservative surgery.
Long-term follow-up (5–10 years) is essential due to the tumor's slow-growing and recurrent nature.
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🔵 Prognosis:
Generally good with complete resection
High recurrence in incomplete excisions
Malignant transformation is extremely rare but possible in long-standing or recurrent lesions
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