Mandible & maxilla

Benign odontogenic tumors

Adenomatoid odontogenic tumor



Last author update: 11 December 2023
Last staff update: 26 March 2024

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PubMed Search: Adenomatoid odontogenic tumor

Joshua Seth Goldfaden, D.D.S.
Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed.
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Cite this page: Goldfaden JS, Bilodeau EA. Adenomatoid odontogenic tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillaadenomatoid.html. Accessed May 19th, 2024.
Definition / general
  • Benign, rare tumor of odontogenic origin
  • Encapsulated, characterized by spindled or cuboidal epithelium forming a nodular pattern, with duct-like structures resulting in cribriform areas; eosinophilic amyloid and calcifications may be seen (Head Neck Pathol 2021;15:71)
Essential features
Terminology
  • Historic terminology (no longer appropriate) includes adenoameloblastoma, adenoameloblastic odontoma, adenomatoid ameloblastoma, pseudoadenomatous ameloblastoma (J Oral Pathol Med 1991;20:149)
  • In 1971, the World Health Organization (WHO) adopted terminology proposed by Philipsen and Birn: adenomatoid odontogenic tumor (Acta Pathol Microbiol Scand 1969;75:375)
ICD coding
  • ICD-O: 9300/0 - adenomatoid odontogenic tumor
  • ICD-10
    • D16.4 - benign neoplasm of bones of skull and face
    • D16.5 - benign neoplasm of lower jaw bone
Epidemiology
  • 2.2 - 7.1% of all odontogenic tumors (J Oral Med Oral Surg 2021;27:19, J Oral Pathol Med 2007;36:383)
    • 87.2% occur in the second or third decade of life but may occur across wide age range
  • ~2:1 female predilection
  • 3 variants of AOT are follicular (pericoronal), extrafollicular and peripheral (J Oral Pathol Med 2007;36:383)
    • Follicular variant accounts for ~71% of all cases
    • Extrafollicular (extracoronal) variant accounts for ~27% of cases
    • Peripheral (extraosseous) variant accounts for 2% of all cases
Sites
Pathophysiology
  • KRAS mutations and MAPK pathway activation are commonly implicated in the pathogenesis in AOT
  • In one series, 71% (27/38) of AOT cases expressed KRAS codon 12 mutations (Mod Pathol 2019;32:799)
Clinical features
  • Usually an asymptomatic swelling (unless secondarily infected)
  • Tooth displacement may be present
Diagnosis
  • May be detected radiographically as an incidental finding or present as clinical swelling
Radiology description
  • Most commonly (~75%) appear as well defined, unilocular radiolucencies (J Oral Pathol Med 2007;36:383)
    • May also appear as mixed density or opaque lesions
  • Encompass impacted teeth and extend beyond the cementoenamel junction and sometimes continue to the apex (Quintessence Int 2022;53:260)
Radiology images

Images hosted on other servers:
Radiolucency, engulfing tooth, extending beyond crown

Radiolucency, engulfing tooth, extending beyond crown

Prognostic factors
  • Prognosis excellent, few recurrences (< 5% documented)
Case reports
Treatment
Gross description
  • 1 - 3 cm in size, unicystic with a thick capsule and soft tissue filling most of the cystic space
Microscopic (histologic) description
  • Epithelium may appear nodular, trabecular, cribriform and form duct-like structures
    • Cells may be spindly, cuboidal or columnar with the nuclei palisading away from the lumen
    • Lesion is enclosed in a thick capsule
  • Amyloid deposits may be present (Quintessence Int 2022;53:260)
  • Calcifications may be seen
  • Calcifying epithelial odontogenic tumor (CEOT)-like areas may be seen
    • AOT - CEOT hybrid lesions have been described as distinct entities; these are customarily considered to be an AOT variant, with the clinical behavior of AOT
  • References: Head Neck Pathol 2017;11:519, Oral Oncol 2005;41:835
Microscopic (histologic) images

Contributed by Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed. and Kelly Magliocca, D.D.S., M.P.H. (Case #490)
Thick fibrous capsule

Thick fibrous capsule

Cribriform areas

Cribriform areas

Rosette-like structure

Rosette-like structure

Cellular area with focal matrix deposition

Cellular area with focal matrix deposition

Nodular appearance

Nodular appearance

Thick capsule

Thick capsule

Positive stains
Molecular / cytogenetics description
  • KRAS mutations and MAPK pathway activation are commonly implicated in the pathogenesis of AOT (Mod Pathol 2019;32:799)
Sample pathology report
  • Anterior maxilla, left, excisional biopsy:
    • Adenomatoid odontogenic tumor, 1.8 cm
Differential diagnosis
  • Adenoid ameloblastoma:
    • May have extensive dentinoid clear cells and occasional ghost cells
    • Morules / whorls, duct-like structures may be seen
    • Lacks thick capsule, radiographically often not well defined
  • Calcifying cystic odontogenic tumor:
    • Ameloblastic epithelium and ghost cells
    • Lacks whorls, duct-like structures and cribriform architecture
  • Calcifying epithelial odontogenic tumor:
    • Sheets of polygonal cells with pleomorphism and prominent intercellular bridging
    • Lacks architectural pleomorphism (whorls, cribriform, duct-like pattern)
Board review style question #1

A 16 year old girl presents with a lesion associated with an impacted maxillary canine. Based on the photomicrograph, what is the lesion?

  1. Adenomatoid odontogenic tumor
  2. Ameloblastoma
  3. Calcifying cystic odontogenic tumor / calcifying odontogenic cyst
  4. Calcifying epithelial odontogenic tumor
Board review style answer #1
A. Adenomatoid odontogenic tumor. The photomicrograph depicts nodular islands and duct-like structures with interspersed calcifications surrounded by a thick fibrous capsule. Answer B is incorrect because ameloblastomas are characterized by ameloblastic epithelium with reverse polarity away from the basement membrane but nodular architecture, encapsulation, calcifications and duct formation are not seen. Answer C is incorrect because calcifying cystic odontogenic tumors / calcifying odontogenic cysts have ameloblastic epithelium, varying numbers of ghost cells and calcifications, lacking the nodular architecture seen. Answer D is incorrect because calcifying epithelial odontogenic tumors lack encapsulation and have sheets, nest and cords of polygonal, pleomorphic cells that exhibit prominent intercellular bridging and amyloid with concentric calcifications.

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