Primordial Cyst

Definition of Primordial Cyst:

A Odontogenic cyst developing from the stellate reticulum which is formed in place of a tooth.

Etiology:

1. Develops through liquefaction and cystic degeneration of stellate reticulum of enamel organ before any calcified enamel or dentine is formed.
2. Usually it may develop from a normal tooth germ, which may be clinically missing from the arch or a supernumerary tooth germ or from dental lamina

Clinical features:

1. Accounts to 5-10 % of the Jaw Cysts
2. It is seen in place of a tooth in an Edentulous area
3. Location: Mandibular third molar region, Ramus region, Pre molar region, incisor region
4. May occur early in life but usually discovered later
5. Usually a tooth is missing
6. Varies in size
7. May expand bone and displace teeth

Radiographic Features:

1. Well demarcated , round or oval radiolucency with sclerotic or reactive border
2. Unilocular or multilocular
3. Seen below or between roots or near to the alveolar ridge
4. More in relation to third molars

Histopathology:

Based on Histology it is of 2 types:

• Keratinized type (more common)
• Non-Keratinized type (less common)

1. Connective tissue capsule shows parallel arrangement of collagen bundles, with varying compactness.
2. Epithelial lining is of stratified squamous – intact or interrupted.
3. Epithelium may also be sometimes non keratinized, with a prominent spinous layer and long and confluent rete ridges and with less conspicuous basal layer.
4. Sometimes the epithelium may be ortho keratinized with a thin to moderate spinous layer and a thin or flattened basal layer.
5. Sometimes the epithelium may also be para keratinized and corrugated in some areas or may also be uniform 6 – 10 cells thick, with a prominent basal layer – with the cells arranged in a PICKET FENCE pattern or TOMB STONE pattern
6. Rete ridge formation is not seen (cf. : odontgenic kerato cyst)
7. Inflammatory infiltrate may be variable.

Treatment:

Radical surgery – Curretage of Bone

Recurrence: Highly recurrent.