Post on 07-May-2015
description
Diagnosis Of Cysts InThe Oral Cavity
Regions
By:SASHI KUMAR MANOHARCRIDepartment Of Oral Medicine & RadiologyVMSDC
Definition
A Cyst is a pathologic cavity having fluid, semi fluid or gaseous content and which is not created by accumulation of pus.
Most cysts, but not all, are lined by epithelium. (KRAMER 1974)
Types Of Cysts
TRUE CYSTS :
Cysts which are lined by epithelium, E.g. Dentigerous Cyst, Radicular Cyst, etc.
PSEUDO CYSTS : Cysts which are not lined by
epithelium, E.g. Solitary Bone Cyst, Aneurismal Bone Cyst, etc.
Parts Of A Cyst
A Cyst has the following parts:
1. Wall 2.Lumen Of Cyst 3.Epithelial Lining
Classification
CYSTS OF THE ORAL REGION
EPITHELIAL LINED
DEVELOPMENTAL
ODONTOGENICNON
ODONTOGENIC
INFLAMMATORY
NON EPITHELIAL LINED
EPITHELIAL-LINED CYSTS
DEVELOPMENTAL ORIGIN i) Odontogenic a) Dentigerous cyst b) Odontogenic Keratocyst c) Lateral Periodontal Cyst d) Gingival cyst
ii) Non-Odontogenic a) Globulomaxillary cyst b) Nasolabial cyst c) Median Palatal cyst
INFLAMMATORY ORIGIN a) Radicular cyst b) Residual cyst c) Paradental cyst
NON-EPITHELIAL LINED CYSTS
a) Solitary Bone Cyst b) Aneurysmal Bone Cyst c) Traumatic Bone Cyst
Frequency Of Epithelial Cysts Of Oral Region
(SHEAR 2006)
52.30%
18.10%
11.60%
8%
5.60%
4.20% SHEAR 2006 Radicular cyst
Dentigerous cyst
Odontogenic keratocyst
Residual cyst
Paradental cyst
Unclassified odontogenic cysts
Criteria For Diagnosis
Based On Clinical Features Based On Anatomical Site Of Jaw Based On Histological Features Based On Aspirate Fluid Based On Radiographic Features
Based On Clinical Features Small cysts are usually symptomatic Large cysts exhibits large swelling and
pain Irregularity of teeth-missing tooth,
impacted tooth, supernumerary tooth, displacement of tooth, non vital tooth, carious tooth, etc
Presence of fluctuation in the swelling upon palpation
Condition of the bone plate-bulging and thinning over the outer cortical bone plate
Based On Anatomical Site Of Jaw Mandibular regions: -3rd molar regions, canine regions-
common impacted tooth regions- Dentigerous Cyst
-angle of mandible, ascending ramus of mandible regions- Odontogenic Keratocyst
-Premolar and molar regions-Lateral Periodontal Membrane- Lateral Periodontal Cyst
-solitary bone cyst and aneursymal bone cyst occurs only in the mandible
Maxillary regions-canine and 3rd molar regions
impacted canines and 3rd molars-Dentigerous Cyst
Based On Histological Features
Sample specimens stained with Eosin & Hemotoxylin stains
Dentigerous Cyst
Dentigerous cysts exhibts two types with variant histologic features
Inflammed Type Non-Inflammed Type
Inflammed Type
Lining shows varying degrees of hyperplasia with rete ridges and occasionally even keratinization.
Wall is composed of mature connective tissue which shows infiltration by chronic inflammatory cells
Focal areas of mucous cells can be seen in the lining. Small odontogenic epithelial islands can be seen in the wall.
Non-Inflammed Type
Lining derived from reduced dental epithelium, consists of 2-4 cell layers of non keratinized epithelium, without
rete ridges.
Wall composed of thin fibrous connective tissue appearing immature, as it is derived from the dental papilla.
NON INFLAMED dentigerous cyst showing a thin nonkeratinized epithelial lining
INFLAMED DENTIGEROUS CYST showing a thicker epitheliallining with hyperplastic rete ridges. The fibrous cyst capsule shows a diffuse chronic inflammatory infiltrate
Periapical Cyst
Cholesterol crystals in from of clefts are often seen in the connective tissue wall, inciting a foreign body giant cell reaction
Originate from disintegrating RBC’s in presence of inflammation
Different types of dystrophic calcification are also seen in connective tissue wall.
Mucus cell metaplasia as well as respiratory cells may be seen in the epithelial lining.
Keratinization if found is due to metaplasia and must not be confused with an OKC.
Quiescent epithelium lining a mature, long-standing periapical cyst
Mucous cells in the surface layer of the stratified squamous epithelial lining of a periapical cyst
Mural nodule of cholesterol-containing granulation tissue fungating into the cavity of a radicular cyst
Odontogenic Keratoyst (OKC)
The epithelial lining is composed of a uniform layer of stratified squamous epithelium,usually six to eight cells in thickness
The epithelium and connective tissue interface is usually flat, and rete ridge formation is inconspicuous.
The basal cell layer has columnar / cuboidal cells with reversely polarized nuclei, imparting a “picket fence” or “tombstone” appearance
The luminal surface shows flattened parakeratotic epithelial cells, which exhibit a wavy or corrugated appearance
Small satellite cysts, cords, or islands of odontogenic epithelium may be seen within the fibrous wall
Epithelial lining is 6 to 8 cells thick, with a hyperchromatic and palisaded basal cell layer
Note the corrugated parakeratotic surface
Satellite microcysts in the wall of an odontogenic keratocyst that appear to be arising direct from an active dental
lamina
Based On Aspirate Fluid
1.Dentigerous Cyst →Clear, pale, straw coloured fluid,
rich in cholesterol crystals
2.Odontogenic Keratocyst →Creamy white, cheese like material, thick aspirate
3.Infected Cyst →Yellowish, foul smelling fluid, pus
discharge
4. Aneurysmal Bone Cyst →Blood on aspiration
5.Solid Tumor Mass →Negative aspiration
Based On Radiographic Features
Various radiographic methods that are used are:
Intra-Oral Periapical Radiography Occlusal Radiography Orthopantomogram CT scan
Radiographic Features Of Cysts
DENTIGEROUS CYST -
Unilocular or occasionally multilocular well-defined, radiolucency with sclerotic margins
3 types - Central Type - Lateral Type - Circumferential Type
Central Type
Lateral Type
Circumferential Type
(a) (b)Figure (a) shows two types of dentigerous cyst The one on the right is lateral typeThe one on the left is circumferential type
Figure (b) shows central type of dentigerous cyst. Appreciate the resorption of the root of the first mandibular molar
PERIAPICAL CYST
Round, ovoid radiolucency with thin sclerotic borders and usually associated with pulpally affected tooth
Loss of lamina dura at the apex of the tooth root
Figure shows well defined radiolucency associated with the apex of a non-vital root filled tooth.
Odontogenic Keratocyst
Unilocular or multilocular well defined radiolucent area with smooth and scalloped radiopaque margins
(a) (b) (c)
Figure (a)shows a small OKC lesionWith scalloped border
Figure (b)shows a larger OKC lesionWith scalloped border
Figure (c)shows a larger multilocular OKC lesionWith scalloped border
Figure shows an OKC lesion that has envelopedAn unerupted tooth to produce a “DENTIGEROUS” appearance
Common Epithelial Cysts Of Oral Region
Dentigerous Cyst Periapical Cyst Odontogenic Keratocyst
Dentigerous Cyst
The dentigerous cyst is defined as a cyst that originates
by the separation of the follicle from around the crown of an unerupted tooth
It develops by accumulation of fluid between the
reduced enamel epithelium and the tooth crownThe dentigerous cyst encloses the crown of an unerupted tooth and is attached to the tooth at the cementoenamel junction
Etiology
Reduced Enamel Epithelium
Dentigerous cyst arises from accumulation of fluid between the reduced enamel epithelium and the tooth crown
Clinical Features
AGE : 1st to 3rd decades.
GENDER : More frequently in males than in females.
SITE : 2/3rd associated with unerupted mandibular 3rdmolar Maxillary canine Mandibular premolar Maxillary 3rd Molar Supernumerary tooth also can be involved
Sign & Symptoms
Most cysts grow to a large size before being discovered while observing a dental x ray to detect the cause of an unerupted tooth.
Large lesions can cause cortical expansion, leading to facial asymmetry, teeth displacement, root resorption, even pain, if infected.
Gross Specimens
Multiple gross specimens of Dentigerous Cyst
Notice the cystic lesionencloses the crown of the tooth and is attached to itscementoenamel junction
Differential Diagnosis
Although dentigerous cysts present a unique feature, but some lesions must be considered in its differential diagnosis :
1. Unicystic ameloblastoma2. Adenomatoid odontogenic tumor.
Complications
Recurrence due to incomplete surgical removal.
Development of ameloblastoma either from lining epithelium or from odontogenic islands in the connective tissue wall.
Development of squamous cell carcinoma either from lining epithelium or from odontogenic islands in the connective tissue wall.
Development of mucoepidermoid carcinoma from mucus secreting cells in the lining.
Periapical Cyst
Synonyms : Radicular cyst Apical Periodontal cyst
Periapical cysts are the most common inflammatory cysts
They arise from the epithelial residues in the periodontal ligament as a result of periapical periodontitis following death and necrosis of the pulp.
Etiology
Periapical cysts usually arises at the apical end of a carious tooth, they arise from the epithelial residues in the periodontal ligament
Carious infection followed by slow necrosis of the pulpal tissues of the tooth
Death of pulpal tissues results in formation of granulation tissue at the apical end of the tooth root
Lession develops to cyst following periapical periodontitis
Clinical Features
Age: 3rd, 4th and 5th decades
Sex: Slightly frequent more in males
Site: Maxillary anterior region and mandibular anterior regions
Frequency: Most common inflammatory cystic lesion of the oral region
Signs & Symptoms
Primarily asymptomatic Usually associated carious tooth and non vital
tooth
Discovered during routine dental X ray exam while
examining a carious tooth
Slowly enlarging hard bony swelling initially. Later, if cysts breaks through cortical plates, lesion becomes fluctuant
Rare in deciduous teeth
Odontogenic Keratocyst (OKC)
OKC’s arises from cell rests of the dental lamina.
They exhibit a different growth mechanism and biologic behavior from the more common dentigerous cyst and radicular cyst.
Several investigations suggest that odontogenic keratocysts
can be regarded as benign cystic neoplasms rather than cysts
Etiology
cell rests of serres (dental lamina)
OKC arises from Islands of epithelial cells that
originate from the oral epithelium and remain in the tissue after inducing tooth development.
Clinical Features
AGE: Occurs over a wide age range and cases have been recorded as early as the first decade and as late as
the ninth In most series there has been a pronounced peak
frequency in the second and third decades
GENDER: More frequently in males than in females
SITE: The mandible is involved far more frequently than the maxilla
50% cases occur in angle region and extending to the ascending ramus and forwards to body of mandible
Signs & Symptoms
Pain, swelling or discharge seen Occasionally, paraesthesia of the lower lip or
teeth. Some are unaware of the lesions until they develop pathological fractures
In many instances, patients are remarkably free of symptoms until the cysts have reached a large size, involving the maxillary sinus and the entire ascending ramus, including the condylar and coronoid processes
occurs because the OKC tends to extend in the medullary cavity and clinically observable expansion of the bone occurs late.
Gross Specimens
Gross specimens of eneucleatedOdontogenic Keratocyst (OKC)
Differential Diagnosis
In case of unilocular radiolucency– Dentigerous cyst, Eruption cyst,Unicystic ameloblastoma etc.
In case of multilocular radiolucencies – Conventional ameloblastoma, Central giant cell granuloma, Aneurysmal
bone cyst etc.
Complications
Malignant transformation of cyst lining rare, but has been reported.
High rate of recurrence
Reasons for recurrence :
1. Thin, fragile lining is very difficult to remove completely.
2. New cysts develop from satellite cysts left behind.
3. New cysts can also develop from basal cells of overlying oral epithelium, especially in ramus – 3rd molar region.
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