• Pindborg tumor
• Aggressive odontogenic neoplasm, associated with an impacted/unerupted tooth
• The only odontogenic tumor to contain amyloid

Histiogenesis

• REE
• Stratum intermedium
• Dental lamina

Site

• Mandible : Maxilla = 2 : 1
• Mandible – Body/ramus
• Gingiva as peripheral tumor

Clinical

• Widening of follicular spaces
• Failure of involved tooth to erupt
• No pain
• Incidental finding on routine radiograph
• Locally infiltrative, not metastasize

Radiology

• Expanded cortices in buccal, lingual and vertical dimensions
• Radiolucency + poorly defined, non cortical borders
• Early: unilocular, multilocular
• Late: “Driven snow appearance”
• Root divergence and resorption
• Impacted tooth displaced with arrested root development

Histology

1. Microsheets of polyhedral, eosinophilic squamous epithelial cells with:

• Focal psammoma bodies (single cell calcifications)
• Concentric calcific deposits (Liesegang rings in amyloid responsible for radiopacities)

2. Tumor cells are:

• Polygonal
• With dysmorphic nuclei
• Interspersed with amyloid deposits
• Containing degenerated keratin filaments

3. Scanty stroma + clear cell variant has clear vacuolated cytoplasm

4. Positive stains: Keratin, Congo red, Thioflavin T for amyloid

Management

• Enucleation for clearly circumscribed early lesion
• Excision with margin – Advanced multilocular/invasive lesions

Picture