10.cysts Of Oral Cavity.2.pptx

CYSTS OF ORAL CAVITY

Definition of cyst  Epithelial lined cavity filled with fluid or semi fluid or

gaseous content  Jaw cysts are "a space within bone lined with epithelium supported by a fibrous connective tissue wall."

Where does the epithelium lining of jaw cysts come from?

Cyst epithelium may come from "rests" left over from tooth development

Cyst epithelium may come from "rests" left over from face development.

Jaw cysts are found in tooth-bearing or facial-fissure areas.  Odontogenic & non odontogenic cysts

Jaw cysts are seen on radiographs; soft-tissue cysts, on clinical examination.

Jaw cysts appear as radiolucent areas on radiographs.

Microscopic Features Common to Most True Jaw Cysts  Debris-filled central cavity  Epithelial lining membrane

 Fibrous connective tissue supporting wall

Cysts

Epithelial

Odontogenic

Non- Epithelial

Non Odontogenic

1. Solitary 2. Aneurysmal 3. Stafne’s

Epithelial cysts

Odontogenic

Developmental

Inflammatory

1. Dentigerous 2. OKC 3. Eruption 4. LPC 5. gingival

1. Radicular 2. Paradental

Non Odontogenic 1. Nasopalatine 2. Nasolabial 3. Globulomaxillary 4. Median

Epithelial Cysts  ODONTOGENIC CYSTS  Odontogenic cysts arise from tooth development epithelium.  reduced enamel epithelium, dental lamina, remnants of

Hertwig's epithelial root sheath.  Inflammatory or Developmental

RADICULAR CYST

RADICULAR  CLINICAL FEATURES

 Commonest  Arises from epithelial rests of malassez  associated with non vital tooth.

 invisible on intraoral clinical examination  May expand to large sizes – egg shell crackling  Apical, lateral, residual

Bacterial endotoxins from necrotic pulp Release of cytokines including GFs Proliferation of epithelial cell rests of malassez in chronic periapical lesion

Death of central cells Central cavity lined by epithelial lining

Cyst expansion Cyst lumen

Hypertonic contents

Cyst wall

Semipermeable membrane

High Osmotic gradient Low Movement of water

Hydrostatic pressure

Cyst wall

Expansion

Inflammatory exudate Cell breakdown products

RADIOGRAPHIC FEATURES  well-demarcated unilocular radiolucency at the tooth apex.

Histopathological features  central debris-filled cavity

 lined with stratified squamous nonkeratinizing epithelium.  The outer fibrous c.t. wall shows many chronic

inflammatory cells suggesting the inflammatory origin of this cyst.  Mucous metaplasia

PARADENTAL / BUCCAL BIFURCATION CYST

Buccal Bifurcation Cyst

Paradental Cyst

Dentigerous Cyst  CLINICAL FEATURES

 commonly arise around impacted teeth  presumed to arise from the reduced enamel epithelium  asymptomatic

 Unicystic ameloblastoma

Compression of follicle by potentially erupting tooth Increased venous pressure of follicle

Fluid transudation Separation of follicle and the tooth

Cyst expansion  Same as for radicular cyst

Radiographically  a well-demarcated, unilocular radiolucency around the

crown of an unerupted tooth

Types of Dentigerous Cysts

Central

circumferential

lateral

HISTOPATHOLOGICAL  Most dentigerous cysts are lined with stratified squamous

nonkeratinizing epithelium (2-4 cell layer thick) supported by a fibrous c.t. wall devoid of inflammation  Mucous metaplasia

Eruption cysts

Odontogenic keratocyst  Origin

 Asymptomatic  Mesio distal expansion  recurrence rates of over 25-62%

radiographic  Their radiolucencies may be small and unilocular or large and

multilocular

histopathology  Keratinizing epithelium

 Actively proliferating epithelium  Palisading of basal layers  Keratin-filled central cavity

 Thin cyst wall (epithelium and c.t.)  Flat epithelium-c.t. interface  Epithelial pouches, satellite cysts

why odontogenic keratocysts are so difficult to remove completely?  First, increased mitotic activity  Second, thin cyst wall – easy tear  Third, Flat epithelium connective tissue interface

 Fourth, satellite cysts  Fifth, finger like cyst extensions

Lateral periodontal cyst  uncommon

 interdental alveolar bone of mandibular premolar area.  Divergence of adjacent teeth  Associated with vital tooth

histopathology  Non keratinized squamous epithelium

 2-3 layers  Fibrous capsule devoid of inflammation.  Focal epithelial thickening

Gingival cyst of new born

Palatal cyst of new born Epstein Pearl Bohn’s Nodule

Calcifying ghost cell odontogenic tumour/cyst

NON ODONTOGENIC CYSTS  Nasolabial

 Nasopalatine  Median cysts  Globulomaxillary

 These arises from fissural epithelium, remained after face

development.

NASOPALATINE  epithelial rests located within the tissues of the incisive canal.

 most common fissural cyst  Asymptomatic  heart-shaped radiolucency located just posterior to the

maxillary incisor teeth.

Histopathology  stratified squamous nonkeratinizing epithelium.

 NPDCs have squamous, columnar, cuboidal, or some

combination of these epithelial types; respiratory epithelium  The presence of glands, blood vessels, and nerves in the cyst wall

Cyst of incisive papilla  Activation of epithelial rests in the incisive papilla may produce a

cyst there.  This is a soft tissue cyst known as the "papilla palatini cyst"  This cyst causes a soft-tissue swelling; it is not visible on radiographs.

NASOLABIAL CYST  remanents of nasolacrimal duct or epithelial remanents

entrapped along the line of fusion of the maxillary and nasal processes.  obliterating the nasolabial fold  Arising in soft tissues, nasolabial cysts are not visible on radiographs.  lined by respiratory epithelium, stratified squamous

epithelium, pseudostratified columnar epithelium or a combination of these.

Globulomaxillary cyst  An uncommon true jaw cyst appearing as a radiolucency

between the roots of vital maxillary lateral and cuspid (canine) teeth  epithelial remnant remained during fusion of the nasal process and maxillary process.  Microscopic examination reveals a cyst that is lined with stratified squamous nonkeratinizing epithelium

Median palatal cysts  Activation of trapped rests in the palatal midline may cause a medial

palatal cyst.  radiolucencies in the midline of the palate well posterior to

the incisive canal.  Median palatal cysts are lined with stratified squamous

nonkeratinizing epithelium

NON EPITHELIAL CYSTS (PSEUDOCYSTS)  Solitary bone cysts  Aneurysmal bone cyst

 Stafne’s idiopathic bone cavity

Common

History of trauma

Asymptomatic

Traumatic bone cyst

Radiograph scalloping

Histology – fibro vascular CT, giant cells

Traumatic Bone Cyst

Scalloping between the roots

Uncommon

Trauma history

painful

Aneurysmal bone cyst

Uni / multi locular radiolucency

Fibro vascular CT. multiple giant cells

Developmental anomaly

Concavity on lingual side mandible

Stafne bone cavity

Histology – normal salivary tissue

Radiographunilocular radiolucency inferior border

SOFT TISSUE CYSTS OF ORAL CAVITY  MUCOCELES

 ORAL LYMPHOEPITHELIAL CYST  EPIDERMOID CYST  DERMOID CYST

ORAL LYMPHOEPITHELIAL CYST  Uncommon

 Develops within the oral lymphoid tissue  Histologically, parakeratinized epithelium with lymphoid

tissue in the cyst wall.

Epidermoid cyst  Very rare in oral cavity

 Common cyst of skin  Histologically lined by orthokeratinized stratified squamous

epithelium with prominent granular layer.

Dermoid cyst  Uncommon

 FOM common site  Lined by orthokeratinized stratified squamous epithelium,

prominent granular layer.  Fibrous wall contains skin appendages such as sebaceous glands, sweat glands and hair follicles.