Odontogenic Cysts & Tumors

Cysts

Cyst	Origin	Key features
Radicular (periapical) cyst	Rests of Malassez	Most common odontogenic cyst; apex of a NONVITAL tooth; a residual cyst remains after extraction
Dentigerous cyst	Reduced enamel epithelium	Most common developmental odontogenic cyst; around the crown of an unerupted tooth, attached at the CEJ; mandibular third molars, maxillary canines
Odontogenic keratocyst	Dental lamina remnants	Posterior mandible and ramus; grows along the bone with little expansion; thin parakeratinized lining with palisaded basal cells; recurs often; PTCH1; multiple OKCs suggest nevoid basal cell carcinoma (Gorlin) syndrome
Orthokeratinized odontogenic cyst	Dental lamina	Often looks like a dentigerous cyst; recurs much less than OKC
Lateral periodontal cyst	Dental lamina rests	Between the roots of VITAL mandibular canine and premolars; botryoid variant is multilocular
Calcifying odontogenic cyst	Odontogenic epithelium	Ghost cells that may calcify
Gingival cysts of the newborn	Dental lamina	Small white nodules on infant alveolar ridges; resolve on their own

Nonodontogenic look-alikes: nasopalatine duct cyst (most common nonodontogenic cyst; heart-shaped, vital incisors) and simple bone cyst (no lining; scallops between roots).

Tumor	Typical patient and site	Key features
Odontoma	Children and teens	Most common odontogenic tumor (a hamartoma). Compound: tooth-like pieces, anterior maxilla. Complex: disorganized mass, posterior jaws
Ameloblastoma	Adults, posterior mandible	Most common clinically significant odontogenic tumor; multilocular 'soap bubble', root resorption, expansion; locally aggressive; unicystic type in younger patients with an impacted third molar
Adenomatoid odontogenic tumor	Teens, anterior maxilla, often around an unerupted canine; females	Well-defined, may contain fine calcifications; 'two-thirds' tumor; enucleation, rarely recurs
Calcifying epithelial odontogenic tumor (Pindborg)	Adults, posterior mandible	Amyloid and Liesegang ring calcifications; 'driven snow' opacities
Ameloblastic fibroma	Children and teens, posterior mandible	Lucent, often with an unerupted tooth
Odontogenic myxoma	Young adults	Multilocular with straight 'tennis racket' septa
Cementoblastoma	Young patients, mandibular first molar	Opaque mass fused to the root with a lucent rim; tooth vital; often painful

Calling a radicular cyst on a vital tooth: radicular cysts need a nonvital tooth (vital teeth suggest other lesions).
Treating OKC like a dentigerous cyst: it recurs often and needs careful removal and long follow-up.
Calling ameloblastoma the most common odontogenic tumor overall: odontoma is.
Missing Gorlin syndrome in a young patient with multiple OKCs.

Pick an answer to see right away whether it is correct and why.

A cyst surrounds the crown of an impacted mandibular third molar and attaches at the CEJ. Most likely:
A 14-year-old has multiple jaw cysts, basal cell carcinomas and palmar pits. The cysts are most likely:
A well-defined lucency sits between the roots of a vital mandibular canine and first premolar in an adult. The most likely diagnosis is:
Which is the most common odontogenic tumor?
A teenage girl has a well-defined lesion with fine calcifications around an unerupted maxillary canine. Most likely:

0 of 5 answered

Answer key: 1 C · 2 A · 3 A · 4 C · 5 B

Dental School Map · Original study material, written and checked by our team; always confirm clinical decisions against current guidelines.