Odontogenic Cysts and Tumors
Core Concepts
Separate developmental from inflammatory cysts and benign from malignant odontogenic tumors. Key entities: radicular and dentigerous cysts, odontogenic keratocyst (OKC), lateral periodontal cyst, calcifying odontogenic cyst, and glandular odontogenic cyst. Tumors include ameloblastoma (follicular, plexiform, unicystic subtypes), adenomatoid odontogenic tumor, odontoma, cementoblastoma, odontogenic myxoma, and ameloblastic carcinoma. Know the significance of BRAF V600E in ameloblastoma and PTCH1 in OKC and keratocystic syndromes.
Common Traps
- Misclassifying unicystic ameloblastoma as a simple cyst because of a cystic lining; mural invasion changes management.
- Forgetting that OKC has high recurrence and may be syndromic (Gorlin syndrome with PTCH1).
- Confusing adenomatoid odontogenic tumor (anterior maxilla, young patients, calcifications) with ameloblastoma.
- Overlooking glandular odontogenic cyst as a low-grade neoplasm with recurrence potential.
Rule of Thumb
Correlate histology with location and age. Anterior maxilla in a teenager with a well-circumscribed radiolucency containing snowflake calcifications suggests AOT; posterior mandible in a 30-year-old with a multilocular radiolucency suggests ameloblastoma or OKC. A worked example: a unilocular pericoronal radiolucency in the mandible of a 20-year-old shows a cystic lining with focal mural proliferation - diagnose unicystic ameloblastoma with mural invasion and treat more aggressively than a dentigerous cyst.
Margin Strategy
Specify whether resection margins are involved and whether the lesion is enucleated or resected, because recurrence risk differs substantially.