AMELOBLASTOMA CT features in various presentations Abstract ID Number 1119 INTRODUCTION • Ameloblastoma (previously called adamantinoma) is the most common epithelial odontogenic tumor. • usually occurs in 2nd to 3rd decade age group [except unicystic variant which is more common in adolescents]. • no gender predilection. • locally aggressive, infiltrative tumor which can rarely turn malignant or metastasize. • It arises from the enamel-forming cells from odontogenic epithelium that failed to regress during embryogenesis. • The ramus and posterior body of mandible is most common location (80%), only 20% of lesions found in the maxilla. • WHO classifies benign ameloblastomas into 1. 2. 3. 4. Solid/multicystic Extra-osseous/peripheral Desmoplastic Unicystic MATERIALS & METHODS: • CT done using 64-MDCT (GE Lightspeed) scanner for 8 cases with swelling in lower jaw/ neighboring area of face selected from this year. Contrast administered to the cases with soft- tissue density swelling. • 5 were painless, 3 painful. • 3 cases had h/o enucleation; 1 with h/o right maxillectomy & mandibulectomy - came with recurrence. • They underwent segmental resection/ mandibulectomy and all were histopathologically proven as ameloblastomas [except one case -ameloblastic carcinoma]. CASE 1: 25-year old female came with painless, progressive swelling over left angle of mouth since 1 year. •well-defined, expansile cystic lesion without any obvious soft tissue component. •in the body and ramus of left hemimandible, with areas of cortical break. •Resorption of first molar root seen •unicystic ameloblastoma on biopsy CASE 2: A 19-year old male presented with a mass in the left lower jaw for 25days. • welldefined, biloculated, heterogeneously enhancing soft tissue expansile lytic lesion • In the ramus, body and angle on the left side of mandible. • left side third molar tooth within. • cortical defects. • biopsy – solid multicystic ameloblastoma. CASE 3: A 42-year old female came with painful, left lower jaw swelling for 15days. • well-defined ,unilocular ,expansile lytic lesion. • from left side of body of mandible crossing midline to symphysis menti • few dense foci within • focal defect only in outer cortex • unicystic ameloblastoma on HPE. CASE 4: 22-year old male h/o painless, slowly growing, swelling in left lower jaw since 8 years ago, underwent cyst enucleation 5 years back, now came with recurred swelling in the same site. • well-defined, unilocular expansile lytic lesion • in the body and angle on left side of the mandible • multiple cortical breaks. • Biopsy -recurrent unicystic ameloblastoma. CASE 5: A 55 year old male with swelling in left lower jaw for 4 years, h/o cyst enucleation [HPE –ameloblastoma], now with recurrent swelling in same site since 2 months. • • • • • heterogeneously enhancing multilocular lytic expansile lesion from body to angle of mandible on left side cortical break, few dense foci HPE- recurrent solid, multicystic ameloblastoma CASE 6: 70-year old male with h/o right maxillectomy 7 years ago, mandibulectomy & neck dissection 3 years ago (histologically ameloblastoma) came now with swelling in the region of right maxilla, pain in right side of face and eyelid edema since 1 month. • heterogeneously enhancing soft tissue lesion from the region of right maxilla • Intracranial extension into temporal lobe, aggressively eroding adjacent bones. • Intraorbital extensionproptosis. • HPE- recurrent solid ameloblastoma. CASE 7: 60-year old male with h/o swelling in the left side of face 4 years, underwent cyst enucleation (HPE-ameloblastoma), now with recurrent swelling in same site since 1 year. • Heterogeneously enhancing soft-tissue, expansile lytic lesion • in the ramus of left mandible • with cortical destruction, • with a cystic component within. • HPE-recurrent solid multicystic ameloblastoma CASE 8: 55-year old male with painful, progressive swelling on right side of face since 1 year. • • • • • • welldefined, multiloculated heterogeneously enhancing soft-tissue lesion with few nonenhancing areas within (necrosis/ cystic areas) from right side of mandible (beak sign positive) cortical destruction, extending into right infratemporal fossa. no evidence of metastasis. HPE - ameloblastic carcinoma. RESULTS Type of Ameloblastoma among 8 cases side of mandible / maxilla affected unicystic  right  solid/multicystic  malignant  left  •Of the total 8 cases, 4 cases were older than 50 years of age when initially diagnosed which is rarer. • Among the 5 solid lesions, all showed heterogeneous contrast enhancement. Bony septae within and root resorption of teeth are commonly associated features with ameloblastomas but among the 8 cases, these were seen only in case 1. Unicystic ameloblastoma is a less encountered variant, more in <30yrs age, almost exclusively asymptomatic & in the posterior mandible. Case 3 was unusual in older age [42 yrs] painful, unicystic ameloblastoma, crossing the midline and occupying the symphysis menti Case 6 was a highly aggressive recurrent ameloblastoma with illdefined margins, extending intracranially and intraorbitally with extensive bone destruction. Cortical defects - both inner and outer cortex were seen in all cases except case 3 with focal outer cortical defect. Case 8 was a very rare primary ameloblastic carcinoma in the right hemimandible with extension to the right infratemporal fossa. CONCLUSION • CT is an excellent imaging modality to characterize the lesion and know the extent of tumor invasion. • Histopathology is mandatory to confirm the diagnosis. • Close differentials are dentigerous cyst, odontogenic keratocyst, odontogenic myxoma and aneurysmal bone cyst. • Treatment of ameloblastoma depends on extent of infiltration. A well-contained lesion is excised with wide margins; en bloc resection is done for an extensive lesion. • Follow-up with CT is important as ameloblastomas have high rate of recurrence. REFERENCES 1. 2. 3. 4. Ceylan Z. Cankurtaran, Barton F. Branstetter IV, Simion I. Chiosea, E. Leon Barnes, Jr. Ameloblastoma and Dentigerous Cyst Associated with Impacted Mandibular Third Molar Tooth. 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