Search This Blog

Friday, June 10, 2011

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.

No comments:

Post a Comment