Dentigerous and periapical cyst / histopathology, clinical and radiographic features

Dentigerous cyst

A odontogenic cyst that surrounds the crown of impacted tooth. It is caused by fluid accumulation between reduced enamel epithelium and crown. Resulting a cyst in which crown is within lumen and roots are outside.

Clinical Feature

▪ It is usually associated with impacted canine or third molar.

▪ It is usually asymptomatic but sometime pain and inflammation is present.

▪ In arch the tooth appear to have missing one tooth.

Radiographic features

It is usually diagnosed by radiograph

▪ It appears well circumcised radiolucency sorrounding the impacted tooth.

▪ Radiolucency limited to cementoenamel junction.

▪ Sorrounding bone is corticated.

Histopathology

▪ Epithelium is  non-keratinized stratified squamous epithelium. 

▪ It is 2 to 10 cell layer thick.

▪ Inflammation can be present.

▪ It has rushton bodies.

▪ Cholesterol and hemosiderin deposit.

▪ Lipid laden macrophages.

▪ Cell layer may have mucous cells known as mucous cell mataplasia.

Importance

Since it has a malignant potential, so it can give rise to

▪ Mucoepidermoid carcimoma

▪ Ameloblastoma

▪ Squamous cell carcinoma

Eruption cyst

An odontogenic cyst with the histologic feature of a dentigerous cyst that sorrounds the tooth crown that has erupted through bone but not through soft tissue and is clinically visible as a soft fluctuant mass on the alveolar ridge.

▪ It does not form intrabony radioluency.

▪ Sometimes it ruptures forming erruption hematoma.

▪ It has variable number of ghosted cell present in cyst lumen.

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