Cysts in the mouth and jaws with histologic Slides

Cysts in the mouth and jaws with histologic Slides

 



Cyst is a pathological cavity lined by a epithelium and containing fluid or semi solid material.

Classification of cyst of the jaws

Developmental cyst

Odontogenic

· Gingival cysts of infants (epstain pearls)

· Odontogenic kerato cyst(primodial cyst)

· Orthokeratinized odontogenic cyst

· Dentigerous (follicular cyst)

· Eruption cyst

· Lateral periodontal cyst

· Gingival cyst of adults

· Glandular odontogenic;sialoodontogenic cyst

Non-odontogenic cyst

· Nasopalatine duct cyst

· Nasolabial cyst

Inflammatory odontogenic cyst

Radicular

· Residual

· Lateral

Paradental

Key features of jaw cysts

· Form sharply defined radiolucencies with smooth borders.

· Fluid may be aspirated and thin walled cysts may be trans illuminated.

· Grow slowly,displacing rather than resorbing teeth.

· Symptoms unless infected and are frequently chance radiographic findings.

· Rarely large enough to cause pathological fracture.

· Form compressible and fluctuent swellings if extending in to soft tissues.

· Appear bluish when close to the mucosal surface

Major factors in the pathogenisis of the cyst formation

· proliferation of epithelial lining and fibrous capsule

· hydrostatic pressure of cystic fluid

· resorption of surrounding bone.

Periapical granuloma

· Sequalae of acute periapical periodontitis

· Ultimate resault of chronic periapical periodontitis-due to acute inflammation that has been inadequately drained and incompletely resolved.

· tooth is usually non vital

· First recognized as rounded area of radiolucency at the apex of the tooth-usually 5mm in diameter and well defined margins.

· Interprited as early cyst formation.

· Chronic periodontitis is typical chronic inflamation characterized by lymphocytes,plasma cells and macrophages.

· Infection is confined by inflammatory cells and granulation tissue surrounds the area.the granulation tissue grows into rounded mass forming granuloma.

· Osteoclasts resorb the bone to accomadate it.

· Spontaneous healing is absent due to tunnel of continuous infection in the root canal

· Variable degrees of proliferation of the epithelial rests of Malaassez in a periapical granuloma at the apex of the dead tooth are common.

· Epithelial proliferation may be sufficient to lead ultimately to cyst formation.

·

Radicular Cyst

· Most common type(Between 20-60yrs)

· Slowly progressing pain less swelling

· Pain and rapid exantion if inflammation/infection occurs.

· First swelling is hard,then become thinner and thinner.(creckling sensation->then fluctuent bluish colour swelling when par of the wall is entirely resorbed.

· Epithelium derived from-epithelial cell rests of malassez-stratified squamous epithelium.Hyaline/Rushton bodies may be seen in the epi.

· Cyst capsule-Colagenous fibrous connective tissue.

· Clefts-within the cyst capsule there are often areas split up by the fine needle shaped clefts.

key features

· form in bone in relation to the root of non vital tooth

· arise by epithelial proliferation in an apical granuloma

· usually asymptomatic unless infected

· Diagnosis-radiograph+non vital tooth+histology

· Do not recur after complete enucleation

· Residual cysts can remain after the causative tooth has been extracted and diagnosis is then less obvious

· Cholesterol crystals often seen in the cyst fluid but not specific to radicular cyst.

Dentigerous Cyst

· Arises in the bone and surrounds the crown of the tooth and is a dilation of the follicle.

· Attached to the neck of the tooth.

· Dentigerous cyst can cause pain or no pain.

· Affected teeth id often displaced.

· commonly associated with unerupted third molars and canines.

· Diagnosis-Radiograph+histological

· May be mistaken radiographically for an odontogenic keratocyst or ameloblastoma.

· Respond to enucleation or masupialisation and do not recur after treatment.

· Occationally pseudoloculation as a resault of trabeculation or ridging of the bony wall can be seen.

· Slow growth causes sclerotic bony outline and well defined cortex.

· Lining of dentigerous cyst typycally consist of thin,sometimes bilaminar,stratified epithellium,frequently with numerous mucous cells.

· Epithelium may be occationally keratinized by metaplasia.

· Fibrous wall similar as Radicular cyst but inflammatory changes are typicaly absent.

Parakeratinized odontogenic cyst/Odontogenic keratocyst

Key features

· 5-11% of jaw cysts

· incident peaks in 2nd and 3rd decades.

· Form intraosseously,most frequently in the posterior alveolar ridge or angle of mandible.mandible 75%,predominantly premolar and molar region

· may grow round the tooth

· Sometimes multilocular radiographically

· Spread extensively along marrow spaces before expanding the jaw

· Frequently recur after enucleation

· Definitive diagnosis only by histopathologically,although clinical and radiographic features may help.

· May be confused with ameloblastoma or with dentigerous cysts radiographically.

· May be part of the basal cell naevus(Gorlin)synndrome

· usually multilocular

Typycal Histological features of odontogenic keratocyst

· Epithelial lining of uniform thickness

· Flat lower border of epithelium

· Clearly defined basal layer of tall cells in parakeratinized cysts

· Thin eosinophilic layer of para keratin

· Cyst lining typically much folded

· Epithelial lining weakly attached to the fibrous wall

· Thin fibrous wall

· Satellite cysts in the wall

· Inflammatory cells typically absent or scanty

Evidance that OKC may be neoplastic

· High proliferative activity of epithelial lining

· Caused by mutation or deletion of PTCH tumor supressor gene

· May contain defects of p16,p53 and other tumor suppressor gene

· Associated with other neoplasms in the basal cell nsevus syndrome

· infiltrative(agressive)growth pattern

· SCC may rearly develop within OKC

· Recurrance

Possible reasons recurrance of OKC

· Thin fragile linings,difficult to enucleate intact

· Finger like cyst extensions in to cancellous bone

· Satellite(daughter) cysts sometimes present in the wall

· More rapid proliferation of keratocyst epithelium

· Formation of additional cysts from other dental lamina remnants(pseudo recurrance)

· Inferior standered of surgical treatment

· possibly a neoplasm

Orthokeratinized Odontogenic(kerato) Cyst

· Less common than para keratinized type

· Lower proliferative activity

· No association between basal cell naevus syndrome

· Usually monolocular

Key features of Lateral periodontal cyst and varients

Lateral periodontal cyst

· Developmental cyst that form beside a vital tooth

· Usually seen ny chance in routine radiographs

· Resemble other odontogenic cysts radiographically,apart from position near the crest of the ridge

· Cause no symptoms but can erode through the bone to extend in to th gingiva

· Microscopically,the lining is squamous or cuboidal epithelium,frequently only one or two cells thick,sometimes with focal thickenings

· Some cells may have clear cytoplasm

· Respond to enucleation

· The relate tooth can be retained if healthy

Sialo-odontogenic cyst

· Also rare and with many features in common with botryoid odontogenic cysts

· Frequently multi locular

· Microscopically,pools of mucin and mucous cells present in the epithelium

· Has a strong tendancy to recur

· Should be consevatively excised

Non odontogenic cysts

naso palatine duct cyst

· Arise from the epithelium of the nasopalatine duct in the incisive canal

· Epithelial ling is stratified squamous epithelium or ciliated columnar epithelium

· Mucos glands and neurovascular bundles often present in the wall

· Often asymptomatic,chance radiographic findings

· Form in a incisive canal region

· Arise from the vestiges of the naso palatine duct and may be lined by columnar respiratory epithelium

· The long sphenopalatine nerve and vessels may be present in the wall

· Can usually be recognized radiographically

· Histological examination necessary to exclude othe cyst types arising at the site

· Do not recur after enucleation

Nasolabial Cyst

· Very common cyst forms outside the bone in the soft tissues,deep to the nso labial fold

· Probably arising from remnants of the nasolabial duct

· Occatonally bilateral

· Lining-Pseudostratified columnar epithelium

· Treatment-Simple excision

· May be complicate if the cyst has perforated the nasal mucosa and discharged in to the nose.

Para Dental Cyst

· Occationally resault from inflammation around partially erupted teeth.

· Particularly mandibular 3rd molars

· Affects males predominantly 20-25yrs

· Affected tooth is vital but show pericoronitis

Histopathologically

· Resembles radicular cyst

· But more inflammatory infiltration in wall.

Dermoid Cyst

· Cyst of soft tissue

· Commnly occur sublingually

· Developmental abnormality or branchial arches/pharyngeal pouches

· Develop belween hyoid and jaw or many form immediatly beneththe tongue

· Filled with desquamated keratin(sometimes)giving a semisolid(salty) like consistancy.

· Have dermal appendages in the wall->give the name dermoid cyst

· Dermoid cyst is a form of cystic teratoma which is similar to structure of dermis

· Derived from embryonic germinal epithelium/acquired entrapted skin/mucosa

· Lined by stratified squamous epithelium and contain skin appendages such as sebaceous glands in CT wall

· Dermoid cysts in the head and neck region appearing symmetrical swellings in the floor of mouth

· There are presumed to derived by entrapment of epithelium remnents during closure of mandibular and hyoid branchial arches

· Sublingual type produce bulge in floor of mouth

· Submental type produce bulge in submental arch(dough-like on palpation)

Epidermoid Cyst

· Small epidermoid cysts may also be found in the tongue,soft palate,buccal mucosa and lips where they are considered to be acquired lesions resaulting from traumatic implantation of surface epithelium

· Simple lesions without skin appandages are epidermoid cysts

Aneurysmal bone Cyst

· Intra osseous lesions consist of blood filled cavernous spaces

· occur in some frequently in jaws and molar areaof younger individuals is the commenest site.

· rapidly expanding lesion

· X-ray multilocular radiolucency

· Thin fibrous CT wall and consist of many blood filled cavernous spaces

· False type of cyst.non epithelialized

Branchial Cyst

· Arising from branchial arch remnants

· it has also been called lymphoepithelial cyst suggesting it's origin from cystic transformation of epithelium entrapted in cervical lymphnodes

· BC originated from 2nd arch->lateral aspect of upper neck near anterior border of sernocledomastoid muscle or at the mandibular angle

· Lesion->circumscribed fluctuent mass

· Young adults no sexual prediction

· Small ones canbe found in the floor of the mouth,Clinically resembles mucous retention cysts

· lined by stratified squamous epithelium

· Occationally columnar or cuboidal

· Cyst wall is composed of lymphoid tissue with scattered germinal centre surrounded by CT.