Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Goldfaden JS, Bilodeau EA. Adenomatoid odontogenic tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillaadenomatoid.html. Accessed March 28th, 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
- Adenomatoid odontogenic tumors (AOTs) are most common in the anterior region of the jaws in young female patients associated with impacted teeth (J Nat Sci Biol Med 2013;4:457)
- Microscopically, AOTs contain spindled, cuboidal, polygonal epithelium, forming duct-like structures, whorls and cribriform architecture surrounded by a thick capsule
- Eosinophilic matrix may be seen, which can calcify (Oral Surg Oral Med Oral Pathol Oral Radiol 2022;133:675)
- Also called the tumor of two - thirds as two - thirds of cases occur in female patients in the maxilla, surrounding an impacted tooth (Oral Oncol 1999;35:125, Surg Pathol Clin 2017;10:177)
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
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
- Anterior maxilla is the most affected (66.6%) (Head Neck Pathol 2012;6:430)
- ~42% of cases are associated with impacted maxillary canines (J Oral Pathol Med 1991;20:149)
- There is a significant predilection for the anterior region (93.3%), with only 6.7% of cases affecting the posterior area, exclusively in the mandible (Head Neck Pathol 2012;6:430)
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
Prognostic factors
- Prognosis excellent, few recurrences (< 5% documented)
Case reports
- 17 year old girl with a 2 cm maxillary lesion surrounding an impacted canine tooth (Case #490)
- 18 year old woman with nonpainful lesion of right anterior maxilla (Anticancer Res 2013;33:2673)
- 28 year old man with impacted tooth (Arch Pathol Lab Med 2003;127:e173)
- 31 year old man with cystic radiolucent lesion of the right mandible (J Oral Med Oral Surg 2021;27:19)
Treatment
- Generally treated by surgical enucleation
- Cases of large lesions that have caused significant bone loss and thinning are often managed by insertion of a drain or via marsupialization (Maxillofac Plast Reconstr Surg 2014;36:173)
- Both surgical and orthodontic modalities can be used to preserve the associated impacted tooth (Maxillofac Plast Reconstr Surg 2014;36:173)
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)
Positive stains
- AE1 / AE3 (Oral Surg Oral Med Oral Pathol Oral Radiol 2022;133:675)
- CK5, CK17 and CK19 (J Oral Pathol Med 2003;32:55)
- Congo red may highlight focal amyloid deposits, especially in CEOT-like areas (Oral Oncol 2005;41:835)
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)
Additional references
Board review style question #1
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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Reference: Adenomatoid odontogenic tumor
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Reference: Adenomatoid odontogenic tumor