Odontogenic Tumors

Odontogenic tumors (ICD-10-GM C41.-: Malignant neoplasm of bone and articular cartilage of other and unspecified locations; ICD-10-GM D16.-: Benign neoplasm of bone and articular cartilage; ICD-10-GM D48.-: Neoplasm of uncertain or unknown behavior in other and unspecified localizations), neoplasms that develop predominantly from embryonic remnants of odontogenic (involved in tooth formation) tissues are grouped together. The term includes hamartomatous (tumor-like, benign tissue changes resulting from defectively differentiated or scattered germinal tissue), non-neoplastic changes via dysplasias (abnormal cell changes) to metastatic malignant neoplasms (daughter tumor-forming malignant neoplasms). Forms of the disease

The majority of odontogenic tumors are benign neoplasms. However, malignant tumors such as carcinomas and sarcomas can also be of odontogenic origin. Due to their genesis from tissues from which teeth normally develop, odontogenic tumors are localized exclusively in the jaw bones or the covering mucosa (there as peripheral changes). Odontogenic tumors per se are rare. Since some forms are extremely rare, only those that are not so rare will be discussed below. Benign neoplasms

  • Ameloblastomas
    • Classic ameloblastoma – intraosseous (within the bone), infiltrative and destructive (destructive).
    • Other rarer ameloblastoma variants: Unicystic ameloblastoma; Peripheral ameloblastoma (synonym: extraosseous ameloblastoma of soft tissues); Desmoplastic ameloblastoma.
  • Ameloblastic fibroma
    • Rarely
    • Benign
    • Neoplastic
    • Often associated with unerupted tooth
  • Adenomatoid odontogenic tumor (AOT) (former synonym: adenoameloblastoma).
    • Benign
    • Non-neoplastic
    • Hamartomatous (tumor-like, benign tissue changes resulting from defectively differentiated or scattered germinal tissue).
    • Intraosseous or peripheral
  • Fibromyxoma (synonyms: myxoma, odontogenic myxoma).
    • Relatively rare
  • Calcifying epithelial odontogenic tumor (KEOT) (former synonym: Pindborg tumor).
    • Rare
  • Calcifying odontogenic cyst (synonyms: odontogenic calcifying ghost cell cyst, odontogenic calcifying ghost cell cyst; formerly: Gorlin cyst).
    • Relatively rare (approximately 2% of all odontogenic tumors).
    • Forms
      • Cyst shape
      • Neoplasia (then: epithelial odontogenic “ghost cell” tumor) – cystic or solid.
  • Odontome
    • Often near a retained tooth (a tooth is considered retained, held in place, whenever it does not appear in the oral cavity at the approximate time of its physiological eruption)
    • Two variants:
      • Complex odontoma
        • All tooth-forming tissues are contained intermingled
      • Compound odontoma (synonyms: composite odontoma, compound odontoma).
        • Consisting of the smallest rudimentary tooth formations.
  • Odontogenic fibroma
    • Rarely
    • Different morphological variants
  • Benign cementoblastoma (synonym: true cementoma).
    • New formation starting from the cementum-forming cells of the tooth.
    • Rarely

Malignant neoplasms

  • Odontogenic carcinomas – very rare and difficult to distinguish by differential diagnosis.
  • Odontogenic sarcomas – extremely rare

Sex ratio:

  • Classic ameloblastoma: 1: 1
  • Desmoplastic ameloblastoma: 1: 1
  • Peripheral ameloblastoma: males are affected twice as often as females.
  • Unicystic ameloblastoma: males: females = 1.5: 1.
  • Ameloblastic fibroma: males: females = 1.4: 1
  • Adenomatoid odontogenic tumor (AOT): women are affected twice as often as men.
  • Fibromyxoma: males: females = 1: 1.5.
  • Calcifying odontogenic cyst: males:females = 1: 1
  • Calcifying epithelial odontogenic tumor (KEOT): 1: 1.
  • Odontomas: Males are more commonly affected than females.
  • Benign cementoblastoma: males: females = 1: 1.2

Peak incidence: odontogenic tumors become clinically manifest in over 90% between the ages of 6 and 20 years.

  • Classic ameloblastoma: peak age 40.2 years. Males appear to be affected four to five years later than females.
  • Desmoplastic ameloblastoma: predominantly in the 4th and 5th decade of life.
  • Unicystic ameloblastoma: mean 16, 5 years with impacted tooth; without impaction 35.2 years.
  • Ameloblastic fibroma: 78% diagnosed before age 20.
  • AOT: Half of all cases are diagnosed between 13 and 19 years of age, distinguishing AOT from other odontogenic tumors. Recurrences (recurrence of the disease) are unknown.
  • Fibromyxoma: The median age is 28 years.
  • Calcifying odontogenic cyst: usually in the 2nd decade.
  • KEOT: median age is 37 years.
  • Odontoma
    • Complex: diagnosed at mean age 20; 84% before age 30.
    • Composite: Diagnostics on average at 17.2 years
  • Benign cementoblastoma is diagnosed about half before the age of 20.

Prevalence (disease frequency): odontogenic tumors are rare diseases. Percentages in the double digits represent odontomas, ameloblastomas and benign cementoblastomas.

  • Odontomas are among the most common odontogenic tumors. They represent up to 73% of all true malformations (hamartomas) in the European and North American regions, but only about 6% in Africa and Asia.
  • Ameloblastomas, on the other hand, are concentrated in the African and Asian regions (58 to 63%).
  • 0.3% to 7% of all odontogenic tumors worldwide are ameloblastic fibroodontomas (only 94 cases described by 2004)

The incidence (frequency of new cases) of benign cementoblastomas is approximately one new case per 1,000,000 population per year. Course and prognosis: Odontogenic tumors are often asymptomatic (without symptoms: incidental finding). Many forms are generally slow growing.

  • Classic ameloblastoma: slow, locally invasive and destructive, usually non-metastatic (“semimalignant”) growth. Even with today’s radical surgical approach, recurrences (recurrence of disease) are possible, and these are more frequent in the maxilla than in the mandible. The recurrence rate with enucleation is given as 20 to 90%.
  • The course of unicystic ameloblastoma is less aggressive than classical ameloblastoma. The recurrence rate is 10% to 25%.
  • Ameloblastic fibroma: The course is painless, slow-growing, and expansive. In 75%, unerupted teeth are found in association with the tumor. Presumptive recurrence is possible with conservative initial therapy with incomplete excision (up to 34.5% of cases). Malignant transformation to ameloblastic fibrosarcoma is conceivable.
  • AOT: slow, progressive growth.
  • Fibromyxoma shows painless, infiltrative and destructive growth and recurs in 25% of cases, often due to incomplete removal of the primary tumor.
  • KEOT grows locally invasive and is also treated with radical surgery. The recurrence rate is 14%.
  • Odontomas grow painlessly and slowly with limited growth potential based on the completion of dentition (permanent dentition). The eruption of a retained tooth after removal of the adjacent odontoma is possible. No recurrences.Note: A tooth is always considered retained, retained when it does not appear in the oral cavity at the approximate time of its physiological eruption.
  • Odontogenic fibroma shows a low recurrence rate.
  • Benign cementoblastomas grow slowly and have unlimited growth potential with an uncertain recurrence rate. Stagnant recurrences are possible.