An epithelial cyst, odontogenic cyst ,inflammatory cyst derived from cell Rest of Malassez , that proliferation in response to inflammation.

1. University of Benghazi
Faculty of Dentistry
Department of Oral Pathology
Radicular cyst (Periapical cyst)
By:Hager Mohammed
Alfakhri

2. A cyst is defined as a pathological cavity lined wholly or in
part by epithelium ,having fluid or semi-fluid content.

3. Classification of cysts of the jaw
Epithelial cyst Non-epithelialized
primary bone cyst
Odontogenic cyst Non- odontogenic
cyst
Developmental
-Odontogenic
keratocyst
-Dentigerous cyst
-Eruption cyst
-Lateral periodontal
cyst
-Gingival cyst
-Glandular cyst
Inflammatory
-Radicular cyst
-Paradental cyst
-Nasopalatine
-Nasolabial cyst
-Median cyst
-Solitary bone cyst
-Aneurysmal bone cyst
-Stafnés idiopathic
bone cavity.

4. Odontogenic cyst
Periapical(radicular cyst)
Lateral periodontal cyst
Gingival cyst of the newborn
Dentigerous cyst
Eruption cyst
Glandular cyst
Odontogenic keratocyst
Calcifying odontogenic cyst
Nonodontogenic cyst
Globulomaxilary lesion
Nasolabial cyst
Median mandibular cyst
Nasopaltine canal cyst
Psedocyst
Aneurysmal bone cyst
Traumatic (simple )bone test
Static bone cyst(Stafnésbone cyst)
Focal osteoporosis bone marrow defect

6. Periapical cyst
-An epithelial cyst, odontogenic cyst ,inflammatory cyst
derived from cell Rest of Malassez , that proliferation
in response to inflammation.
-Odontogenic cyst
A cyst in which lining of the lumen derived from epithelium
in tooth development.
-Non-odontogenic cyst
The epithelial lining is derived from sources other than the
tooth organ.

7. Periapical cyst/Radicular cyst
-Types of Radicular cyst (periapical cyst)
1.Apical 70%
2.Lateral 20%
3.Residual
Most common location:
1.Maxillary anterior region
2.Maxillary posterior region
3.Mandibularposterior region
4.Mandibular anterior region

8. Periapical cyst-Epidemiology
-Worldwide
-Common-constitutes approx one half to three fourth of all cyst in the
jaw
-Relative frequency :60-70%
-Frequent in age between 20-60years(rarely in <10 years Ago)
(Peak in third through six decades)
-M/F ratio 3:2
-Maxilla is 3 times more affected than mandible

9. Periapical cyst-clinical features
-Usually asymptomatic
-Slowly progressive
If infection enters, the swelling painful and
rapidly expands
(partly due to inflammatory edema)
-Initially swelling round and hard
-Later, part of wall is resorbed…leaving a soft
fluctuant swelling ,blush in color ,beneath the
mucous membrane .

10. Periapical cyst-Pathogenesis
Phases:
1.Phase of initiation
2.Phase of cyst formation
3.Phase of enlargement

11. Periapical cyst-Pathogenesis
(PHASE1)phase of initiation:
-Stimulation of cell rest of Malassez in response to INFLAMMATION elicited by
.Bacterial infection of pulp
.Direct response to necrotic pulp tissue.
(PHASE2)phase of cyst formation:
-Epithelial cells derive their nutrient by diffusion from adjacent C.T
,progressive growth of an epithelial island moves the innermost cells of the
island away from the nutrients.
-Ultimately these innermost cell undergo ischemic liquefactive necrosis
,establishing central cavity (lumen)surrounding by viable epithelium.
(PHASE3)phase of cyst expansion:
-Breakdown of cellular debris within cyst lumen.
-the protein concentration ..increased osmotic pressure
-in fluid transport into the lumen from the C.T side.
-Ingress thus assist in outward growth of a cyst.

12. Periapical cyst-Pathogenesis
Major factors in the Pathogenesis of cyst formation
.Epithelial proliferation
.Hydrostatic effects cyst fluid
.Bone resorbing factors
-Infection from pulp chamber induces inflammation .
-Cyst fluid contain protein which exert osmotic pressure.
-Hydrostatic pressure within cyst is about 70cm of
water(higher than capillary pressure).
-Bone resorption factors PGE2,PGE3 with osteoclast bone
resorption ,the cyst expand.

14. Periapical cyst -Histopathology
.Lumen(cavity):
-Contains cyst fluid ;which is usually watery ,straw -color and
opalescent.
-Sometimes more viscid and yellowish.
-sometime shimmers with cholesterol crystals.
-Protein content of fluid .
.Epithelial Lining:
-Non-keratinized stratified squamous
epithelium.
-Lack a well-defined basal cell layer.
-Thick,irregular,hyperplastic or net like forming
rings and arcades.
-Hyaline Bodies(Rushton Bodies)may be found.
-Transmigration of inflammatory cells through
epithelium is common with neutrophils and less
lymphocyte.

15. Periapical cyst -Histopathology
.Wall/capsule:
-Composed of collagenous fibrous connective tissue .
-Capsule is vascular and infiltrated by chronic inflammatory cell.
-Plasma cell are prominent or often predominate.
-Russell bodies are often found.
-Cholesterol crystal associated with multinucleate giant
cells(foreign body type).they may erode through epithelial lining
and extrude into cyst lumen.
-Foam cells(lipid-filled macrophages)

16. Early radicular cyst showing
variation in thickness of the
epithelial lining
Periapical granuloma
containing proliferation
arcades of squamous
epithelium derived
from the rest of
Malassez showing early
cystic break down

17. Cholesterol cleft and
hemosiderin deposit (blue)
Epithelial lining of radicular
cyst

19. Periapical cyst –Radiology
-Periapical cyst is well circumscribed
-Distinct line of cortication separating it from surrounding bone.
-May be associated with resorption of apices of teeth, displacement of
teeth or both.

20. References
-Cawson's essentials of oral pathology and oral medicine-8th edition
-Contemporary oral and maxillofacial pathology-2nd edition
-Oral pathology clinical pathologic correlations regezi-5th edition
-Soames and southam oral pathology-4th edition