1. CT features in various presentations
AMELOBLASTOMA
CT features in various presentations
Abstract ID Number 1119

2. 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
Solid/multicystic
Extra-osseous/peripheral
Desmoplastic
Unicystic

3. 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].

4. Resorption of first molar root seen unicystic ameloblastoma on biopsy
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

5. CASE 2: A 19-year old male presented with a mass in the left lower jaw for 25days.

6. 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.

7. 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.

8. 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.

9. well-defined, unilocular expansile lytic lesion
in the body and angle on left side of the mandible
multiple cortical breaks.
Biopsy -recurrent unicystic ameloblastoma.

10. 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

11. 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.

12. heterogeneously enhancing soft tissue lesion from the region of right maxilla
Intracranial extension into temporal lobe, aggressively eroding adjacent bones.
Intraorbital extension-proptosis.
HPE- recurrent solid ameloblastoma.

13. 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.

14. 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

15. CASE 8: 55-year old male with painful, progressive swelling on right side of face since 1 year.

16. welldefined, multiloculated heterogeneously enhancing soft-tissue lesion with few non-enhancing 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.

17. RESULTS
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.

18. 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 ill-defined margins, extending intracranially and intraorbitally with extensive bone destruction.
Case 8 was a very rare primary ameloblastic carcinoma in the right hemimandible with extension to the right infratemporal fossa.
Cortical defects - both inner and outer cortex were seen in all cases except case 3 with focal outer cortical defect.
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.

19. 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.

20. REFERENCES
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. RadioGraphics 2010; 30:1415–20.
More C, Tailor M, Patel HJ, Asrani M, Thakkar K, Adalja C. Radiographic analysis of ameloblastoma: A retrospective study. Indian J Dent Res 2012;23:698.
Dunfee BL, Sakai O, Pistey, R, Gohel A. Radiologic and Pathologic Characteristics of Benign and Malignant Lesions of the Mandible. RadioGraphics 2006; 26:1751–68.
Scholl RJ, Kellett HM, Neumann DP, Lurie AG. Cysts and cystic lesions of the mandible: clinical and radiologic-histopathologic review. RadioGraphics 1999;19(5):1107–24.