Mandible-Maxilla
Malignant tumors
Ameloblastic fibrosarcoma

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

Revised: 20 January 2016, last major update January 2016

Copyright: (c) 2004-2016, PathologyOutlines.com, Inc.

PubMed Search: Ameloblastic fibrosarcoma [title] mandible
Cite this page: Ameloblastic fibrosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillaameloblasticfibrosarcoma.html. Accessed December 9th, 2016.
Definition / General
  • Rare mixed odontogenic tumor that consists of a benign ameloblastic epithelium and a malignant mesenchymal stroma
  • Thought to be malignant counterpart to ameloblastic fibroma
Terminology
  • Ameloblastic fibrosarcoma
  • Ameloblastic fibrodentinosarcoma: used when dentin is present within the malignant stroma
  • Ameloblastic fibroodontosarcoma: used when enamel is present within the malignant stroma
Epidemiology
  • Rare, < 100 case reports in English literature
  • More common in males (1.5 - 1.6:1)
  • Mean age: 3rd decade
Sites
  • More common in mandible (80%); favors posterior mandible
  • Can have maxillary involvement; may extend into sinus
Etiology
  • Close to half (45%) arise from ameloblastic fibroma
  • De novo tumors tend to occur in younger patients
Clinical Features
  • Patients often present with swelling and pain
  • Occasionally painless facial mass with accompanying paresthesia
Diagnosis
  • Diagnosis dependent on clinical, radiologic and pathologic correlation
Radiology Description
  • Appears as an expansive, multilocular radiolucent lesion
  • Often shows cortical perforation
Radiology Images

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Ill-defined radiolucent lesion

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Panoramic radiographs

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Multilocular radiolucent lesion

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CT

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Isodense area

Prognostic Factors
  • Locally aggressive with high (~45%) recurrence
  • Multiple recurrences are not uncommon
  • Distant metastases are not as common
Case Reports
Treatment
  • Surgical resection with a wide margin is the optimal treatment strategy
  • Adjuvant chemotherapy and radiotherapy as needed; may reduce the recurrence rate and enhance the quality of life
Clinical Images

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Gross swelling

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Swelling, lower left mandible

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Swelling without ulceration

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Massive intraoral extension

Gross Images

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Left half of mandible

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Cross-section

Micro Description
  • Biphasic with benign epithelium and malignant stroma:
    • Benign odontogenic epithelium with “ameloblastic” appearance of basaloid odontogenic epithelium
      • Strands, cords and nests of odontogenic epithelium
      • Focally, larger tumor islands may show peripheral palisading, reverse polarization, stellate reticulum-like material
    • Malignant stroma consisting of variably spindled cells with pleomorphism, hyperchromasia, increased mitoses
      • Stromal cells can be arranged in a herringbone or storiform pattern
Micro Images

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Benign odontogenic epithelium

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Odontogenic epithelium

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Low grade malignant neoplasm

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Small nests, islands

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Epithelial dysplasia

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AE1/AE3, vimentin, Ki67

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PCNA, p53

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Ki67, p53

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Pan-cytokeratin, vimentin, Ki67

Differential Diagnosis
  • Ameloblastic fibroma
    • Tends to occur at younger age (first two decades of life)
    • Histologically, may share same features within the odontogenic epithelial component strands, cords and islands that may exhibit peripheral palisading, reverse polarization and stellate reticulum
    • However, stroma is less cellular and more primitive, delicate and lobular in appearance
    • Lacks sarcomatous features (pleomorphism, hyperchromasia, atypical mitoses)
    • Some case reports indicate Ki-67 in the stroma is higher in ameloblastic fibrosarcoma when compared to ameloblastic fibroma (10x increase)
  • Ameloblastoma
    • Similar to ameloblastic fibrosarcoma and ameloblastic fibroma, may show some histological overlap of the basaloid odontogenic epithelial islands (peripheral palisading, reverse polarization, stellate reticulum)
    • Does not have malignant stroma (spindle cells with pleomorphism, hyperchromasia, atypical mitoses)
  • Fibrosarcoma
    • Rare, malignant tumor of fibroblasts with herringbone architecture and variable collagen
    • Usually deep soft tissue of lower extremities or trunk, only rarely in retroperitoneum or mediastinum
    • Tends to occur in slightly older population (ages 40 - 55)
    • Should have no odontogenic or ameloblastic epithelial component