Mandible-Maxilla
Malignant tumors
Ameloblastic carcinoma

Author: Anthony Martinez, M.D. (see Authors page)
Editor: Kelly R. Magliocca, M.D.

Revised: 29 December 2015, last major update December 2015

Copyright: (c) 2004-2015, PathologyOutlines.com, Inc.

PubMed Search: Ameloblastic carcinoma [title] mandible maxilla
Cite this page: Ameloblastic carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillaameloblasticcarcinoma.html. Accessed December 7th, 2016.
Definition / General
  • Rare epithelial odontogenic tumor with histologic features of an ameloblastoma with marked cytologic atypia
Epidemiology
  • Rare, < 100 case reports in English literature
  • Represent < 1% of all odontogenic tumors
Sites
  • More common in mandible (~80%), particularly posterior mandible
  • Rare reports of maxillary involvement
Etiology
  • Majority arise de novo
  • Less commonly arise from pre-existing ameloblastoma, and are considered secondary or dedifferentiated lesions
Clinical Features
  • May be painful as they cause expansion of the jaw, grow rapidly and perforate the cortex
  • "Expansion" or "hard mass" is the most common chief complaint
  • Other complaints include toothache, ulceration, trismus and facial asymmetry
Diagnosis
  • Requires clinical, radiologic and pathologic correlation
Prognostic Factors
  • Malignant lesions have 30% recurrence rate, 22% metastasis rate
  • 5 year survival is 70% without metastases, 20% with metastases
Radiology Description
  • On radiograph, well-defined unilocular or multilocular radiolucent lesion
  • Often shows cortical expansion with perforation
Radiology Images

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Orthopantomogram

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Lucent lesion

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Axial non-contrast CT

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Axial MRI

Case Reports
Treatment
  • Composite surgical resection, with adjuvant radiation and chemotherapy as appropriate
Clinical Images

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Extraoral swelling

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Pus discharge

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Intra-oral swelling

Gross Images
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Resected specimen

Micro Description
  • Variable features of amelobastoma: peripheral palisading, reverse polarization, stellate reticulum
  • Features of malignancy include cytological atypia, high N:C ratio, increased mitoses with atypical forms, necrosis
Micro Images

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Low power

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Cytological atypia

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Necrosis

Differential Diagnosis
  • Ameloblastoma
    • Histologically, may share some of same features such as peripheral palisading, reverse polarization and stellate reticulum, but should not show features of malignancy (pleomorphism with hyperchromasia, atypical mitoses)
  • Clear cell odontogenic carcinoma
    • Malignant epithelial odontogenic tumor composed primarily of nests and islands of clear cells
    • May have focal peripheral palisading similar to ameloblastoma, but not as much cytologic atypia as ameloblastic carcinoma
    • More common in anterior mandible
    • EWSR mutation
  • Malignant ameloblastoma
    • Like amelobastoma histologically but termed "malignant" after discovery of metastases
    • Should not show any cytologic features of malignancy
  • Metastatic disease
  • Primary intraosseous squamous cell carcinoma
    • Carcinoma composed of moderately to poorly differentiated squamous epithelial cells with variable keratinization
    • Also derived from odontogenic epithelium