Calcifying Epithelial Odontogenic Tumour (Pindborg tumour)

Also called Pindborg tumour since discovered by Dr Jens J Pindborg.







Definition:
It is an uncommon benign, odontogenic epithelial neoplasm.

Cells of origin:
1. Stratum intermedium (exception)
2. Remnants of dental lamina or reduced enamel epithelium

Etiology: Enigmatic

Clinical features:
Age: Middle age (Average 40 years)
Site: Mandible : Maxilla = 2:1, Molar(posterior) region: Bicuspids = 3:1
- Asymptomatic mostly but painless swelling (52% impacted or unerupted tooth)
- Extraosseous lesion site: Gingiva and is associated with impacted tooth giving radiolucent lesion mimicking endogenous cyt initially i.e. giving honeycomb appearance.

Radiographic features:
- Mostly shows a combined pattern of radiolucency and radiopacity
with irregular bony trabeculae traversing into radiolucent area in many directions, giving a multilocular or honeycomb pattern.
- Scattered flecks of calcification throughout the radiolucency gives driven snow appearance.
- CT: Expansion and thinning of buccal and lingual cortical bony plates
- MRI:
     Hypointense lesion on T1-weighted images
     Hyperintense on lesion T2-weighted images

Histologic features:
- Scattered small islands of cells in  bland fibrous connective tissue, arranged in cords or rows mimicking adenocarcinoma

- Tumour cells: 
 Well-outlined cell border and prominent intercellular bridges (desmosomes and hemidesmosomes)

- Nuclear morphology:
 Pleomorphic, with giant nuclei and multinucleated

- Cytoplasm:
Richly homogenous eosinophilic substance (amyloid, glycoprotein, keratin, basal lamina or enamel matrix) →Characteristic feature, occasionally glycogen rich clear cells
Note: Stains used
   1. Crystal violet
   2. Congo red
   3. Fluoresces under UV light with thioflavin T

- Cell size:
 Normal squamous cells similar to oral mucosa cells and much larger irregular cells as seen in dysplasia

- Liesegang rings: Characteristic feature

Treatment and prognosis:
- Small intrabony lesions: Enucleation or curettage
- Recurrent or persistent or large (>4 cm) lesions: Segmental resection of jaw bone

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