Mandible & maxilla

• Pathogenesis is unknown
• Mutations have been reported, although they may not represent driver mutations (J Clin Pathol 2018;71:279, J Oral Pathol Med 2014;43:183, Oral Oncol 2010;46:387, Anticancer Res 2009;29:3065)

Contributed by David Owsley, D.M.D. and George Arquitt, D.D.S., M.D.


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• Sheets, nests or cords of polyhedral cells often with nuclear pleomorphism 
• Mitotic figures are rare or absent 
• Nuclei may be hyperchromatic, angular or crinkled 
• Distinct cell borders often with prominent intercellular bridges (prickles)
• Amorphous, congophilic eosinophilic amyloid
  • Amyloid may calcify, forming masses or Liesegang rings (round basophilic calcifications with concentric laminations)
  • Pseudoglandular structures and cystic spaces have been described (Head Neck Pathol 2018;12:598, Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:773) 
• Clear cell variant
  • Clear cell variant shows focal to diffuse clear cells
• Noncalcifying / Langerhans cell rich variants
  • Langerhans cell rich variant is an area of diagnostic uncertainty, with some suggesting that it represents an amyloid rich subtype of odontogenic fibroma and others suggesting it should be classified as a unique subtype of CEOT (Oral Surg Oral Med Oral Pathol Oral Radiol 2018;126:513, Head Neck Pathol 2023;17:313, Head Neck Pathol 2023;17:1011)
• At least 24 cases of combined adenomatoid odontogenic tumors - CEOT have been reported
  • Clinically, these tumors behave indolently, similar to adenomatoid odontogenic tumors (Oral Surg Oral Med Oral Pathol 1983;55:487, Oral Oncol 1999;35:125)

Contributed by Molly Housley Smith, D.M.D.

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• Cytokeratins, CK5/6, p63, p40 (Korean J Pathol 2014;48:175)
• Amyloid highlighted by Congo red with apple green birefringence
• Clear cell subtype has varying amounts of PAS positive, diastase labile accumulation

A patient presents with a well defined radiolucency with speckled radiopacities in the posterior mandible. Biopsy reveals large islands of polyhedral cells intermixed with globules of amyloid which stain with Congo red. What is the diagnosis?

1. Ameloblastoma
2. Calcifying epithelial odontogenic tumor
3. Calcifying odontogenic cyst
4. Central mucoepidermoid carcinoma

B. Calcifying epithelial odontogenic tumor. It presents as a mixed radiolucent / radiopaque lesion with epithelial cells and amyloid material. Answer A is incorrect because ameloblastoma characteristically shows columnar cells, which exhibit peripheral palisading, reverse polarity and apical vacuolization. Answer C is incorrect because calcifying odontogenic cyst characteristically shows a cystic structure with ghost cells. Answer D is incorrect because central mucoepidermoid carcinoma demonstrates a proliferation of mucous cells, epidermoid cells and intermediate cells without the presence of congophilic amyloid.

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Reference: Calcifying epithelial odontogenic tumor

Which odontogenic tumor contains Congo red staining with green birefringence under polarized light? This tumor does not demonstrate EWSR1 rearrangements, differentiating it from other entities in the differential diagnosis.

1. Ameloblastoma
2. Calcifying epithelial odontogenic tumor
3. Clear cell odontogenic carcinoma
4. Gorlin cyst

B. Calcifying epithelial odontogenic tumor. It demonstrates islands, nests or cords of often pleomorphic appearing polyhedral cells intermixed with Congo red positive amyloid material. Answer A is incorrect because ameloblastoma is not positive for amyloid material upon staining with Congo red. Answer C is incorrect because clear cell odontogenic carcinoma frequently shows EWSR1 rearrangements. Answer D is incorrect because Gorlin cyst, often known as calcifying odontogenic cyst, is a cystic structure with ghost cells. Congo red positivity is not noted in calcifying odontogenic cysts.

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Reference: Calcifying epithelial odontogenic tumor