Oral Pathology II Forth Year

1. Cyst of the jaws and neck
Cyst  epithelium lined pathologic cavity
Classification :
1. Odontogenic cyst
2. Non-odontogenic cyst
3. Pseudocyst (differ from true cyst in which they lack an epithelium lining).
4. Soft tissue cyst of the neck.
Epithelial rests (remnants) surrounding the tooth source of odontgenic cyst
1 periapical (radicular cyst):
periapical granuloma initiated and maintained by degradation products of necrotic pulp which stimulates
rests of malassez to proliferate  this will help to separate the inflammatory stimulus from bone
Etiology: breakdown of cellular debris within the cyst lumen raises the protein concentration producing in
increasing in osmotic pressure , the result is fluid transport across the epithelial cells into the lumen from the
connective tissue side
Clinical features:
- most common cyst.
- Age 3rd to 6th decades
- Maxilla > Mandible
-Asymptomatic
-Non-vital tooth
- x-ray :
- can't differ from granuloma,both has radiolucency with a narrow margin size 1.5 cm
- radiopaque line surrounding the cyst indicates that’s its slow in growing cancer ill- defined border (fast
growing)
Histopathology:
- lined by non-keratinized stratified squamous epithelium.
- PMNs transmigrated through the epithelium.
- Connective tissue with mixed inflammatory cell population.
- Foci of dystrophic calcification, cholesterol and giant cell.
Differential diagnosis :
periapical granuloma, Periapical scar(previous surgery), Periapical cement-osseosus dysplasia, Traumatic
bone cyst ( posterior region ), Odontogenic tumor, giant cell lesion, metastatic disease and primary osseous
tumor

2. Treatment and prognosis:
- extraction + curettage of apical zone
- Residual cyst develop if cyst lining not properly removed.
- RCT with apicoectomy.
- RCT only ( persistant periapical lesion ).
- If not treated, bone resorption and weakening of the jaw will occur.
2.Lateral periodontal cyst(LPC):
non-keratinized developmental cyst occurring adjacent or lateral to root and its similar to gingival cyst of
adult
Etiology:
related to proliferation of dental lamina within the bone. However, gingival cyst from dental lamina
between epithelium and periosteum.
Clinical features:
- Mand(premolar and canine). Maxila (lateral incisor).
- Male predilection 2:1 female for LPC ,equal for gingival cyst.
- Age5th and 6th decades.
- Gingival appear as small swelling in relation to the dental papilla.
- LPC appear as radiolucent lesion with opaque margin.
- Tooth is vital.
Histopathology:
- lined by thin, non-keratinized epithelium.
- Clusters of glycogen – rich clear epithelial cells.
Differential diagnosis:
- Lateral radicular cyst (lateral root canal) which is non- vital.
- Odontogenic tumor.
- Gingival mucocele(gingival cyst).
Treatment:
-Local excision.

3. 3.Gingival cyst of new born :
- appear as nodule along ridge of neonate.
- Form from fragments of dental lamina.
- Degenerate and involute or rupture before 3 months of age.
- Lined by stratified squamous epithelium.
4.Dentigerous cyst:
- attached to tooth cervix(enamel-cemental junction) and enclose the crown of unerupted tooth.
Etiology :
proliferation of enamel organ remnant or reduced enamel epithelium.
Clinical feature:
- 2nd most common.
- 3rd molars and maxillary canine.
- Age 2nd and 3rd decades.
- Male 1.6:1female.
- Asymptomatic, except in delayed eruption.
- Significant size.
x-ray :
well-defined uniocular or multiocular radiolucency.
histopathology:
- lined by nonkeratinized stratified squamous epithelium.
- uninflammed.
differential diagnosis:
odontgenic keratocyst, ameloblastoma, odontogenic tumor.
Treatment:
remove the tooth and enuclation of the lesion.

4. 6. Eruption cyst
- result from accumulation of food within the follicular space.
- food impact between the crown and reduced enamel epithelium.
- no treatment because tooth will erupt through the lesion.
7. Glandular Odontogenic Cyst " mucous producing salivary gland tumor "
some histologic features that suggested a mucus producing salivary gland tumor.
mandible 80% especially anterior mandible. Maxillary lesion tend to be localized.
jaw expansion is not uncommon.
the gender ratio is equal.
common age is 50 years.
x-ray : multioccular, wide size range.
Histopath :
- lined by non-keratinized epithelium.
- cuboidal cells often ciliated.
- mucous cells.
Tx :
- considered locally aggressive, it need :
1- peripheral curettage or excision ( simple curettage will not heal )
2- follow up ( recurrence 25% )
8. Ortho Keratinized Odontogenic Cyst
- occur in young adult, 2 : 1 male to female.
- most commonly involve mandibular third molar.
- asymptomatic, uniocular pericoronal lesion.
- clinically & radiographic similar to dentigerous cyst.
Histopath :
- orthokeratinized, stratified squamous epithelium.
- no palisaded basal layer.
- not associated with gorlin syndrome.
- yellowish keratin when aspiration.

5. Differential diagnosis :
dentigerous cyst, ameloblastoma, myxoma, adenomatoid odontogenic tumor & ameloblastic fibroma.
Tx :
enucleation & curettage ( 2% recurrence )
9. Calcifying Odontogenic Cyst :
- developmental cyst derived from odontogenic epithelium remnants within the gingival, maxilla &
mandible.
- ghost cell keratinization ( unneucleated ).
Clinical features :
- peak incidence in 2nd decade & predilection for female.
- irregular size calcification.
- 70% in maxilla.
X-ray :
uni or multioccular radiolucency with discrete margin.
Histopath :
fibrous CT wall lined by odontogenic epithelium.
intraluminal epithelium proliferation occasionally obscure the cyst lumen.
ghost cell keratinization ( free basophilic granularity ).
Differential Diagnosis :
- dentigerous cyst, ameloblastoma, ameloblastic fibroodontoma, clacifying epithelial odontogenic
tumor, odontoma & OKC.
Tx :
aggressive need more than simple curettage & follow up due to recurrence.
Non Odontogenic Cyst
1. Globumaxillary cystlesion
- it's reported to be fissural cyst that arise from the epithelium entrapped during fusion of the globular
portion of the medial nasal process with maxillary process.
- concept is questionable when the radiolucency occur between maxillay lateral incisor and canine (
considere odontogenic lesion ).

6. 2. Nasolabial Cyst :
- is soft tissue cyst of upper lips. The chief clinical sign is soft tissue swelling may present over soft
tissue of canine region or mucobuccal fold.
- the pathogensis unclear but suggested that the lesion represent cystic change of the solid cord
remnants of cells that form nasolacrimal duct.
- 4th to 5th decade, 4 : 1 female predilection.
histopath :
pseudo stratified columnar epithelium with numerous goblet cells.
Tx :
curettage.
3. Naspalatine Canal Cyst
- located at nasopalatine canal or soft tissue at canal opening.
- result from epithelium remnant of paired embryonic nasopalatine canal within incisive canal.
Clinical features :
- common cyst, symmetric swelling in the anterior region of the palatal midline or as midline
radiolucency.
- 4th to 6th decades, men are affected more.
- asymptomatic, with the clinical sign of swelling usually calling attention to the lesion.
x-ray :
radiolucent, with sharply defined margin & heart shape.
Histopath :
range between stratified squamous epithelium to pseudostratified columnar epithelium.
Differential diagnosis :
periapical granuloma, radicular cyst, widening of the canal.
Tx :
surgical enucleation.

7. Pseudocyst
1. Aneurysmal Bone Cyst ABC
- radiograph : cyst like but microscopically no epithelium lining.
- 40% mandible, 25% maxilla.
- the pathogensis remain obscure.
- is regarded as reactive ( there is stimulus ).
- is suggested that antecedent primary lesion initiate a vascular malformation resulting in a secondary
lesion or ABC.
Clinical features :
- in people younger than 30 years & slight more in female.
- pain in 50% of cases.
- firm, non pulsating swelling ( common sign ).
- when alveolar segment involved, teeth may be displaced withwithout root resorption.
Histopath :
- fibrous CT stroma contain variable no. of multineucleated giant cells, sinusoidal blood spaces are
lined by fibroblast & macrophages.
Differential diagnosis :
OKC, centeral giant cell granuloma, ameloblastic fibroma.
Tx :
curettage with supplemental cryotherapy.
2. Traumatic Bone Cyst
- is an empty intrabony cavity that lack an epithelium lining
- mostly in the mandible.
- pathogenesis is unknown but in some cases associated with antecedent trauma.
- inducing of hematoma has been hypothesized as forming within the intramedullary portion of bone.
Rather than organizing the clot break down leaving an empty bone cavity.
- teenager most common affected & equal gender distribution.
- swelling is occasionally seen & pain infrequently needed.
x-ray :
well delineated area of radiolucency with irregular but defined edge.

8. Histopath :
delicate, well vascularized, fibrous CT without epithelium lining.
Tx :
establish bleeding before closure.
3. Static Bone Cyst
- developmental lesion in the posterior lingual mandible bilaterally and some tomes anterior to the 1st
molar of the mandible, commonly in adults men.
- cause is unknown but suggested is due to entrapment of salivary gland or other soft tissue during
the development of the mandible. Other have suggested that the cause is lingual mandibulr cortical
erosion from hyperplastic salivary gland tissue.
- asymptomatic, oval radiolucency of inferior border of the mandible at a level of IAC.
- no treatment required.
4. Focal Osteoporotic Bone Marrow Defect
- symptomatic, focal radiolucency in area where hematopoisis is normally seen.
- pathogensis unknown but there are 3 theories :
1- abnormal healing following tooth extraction.
2- residual remnant of fetal marrow may persist into adulthood, these presenting focal
lucency.
3- may merely represent a focus of extramedullary hematopoiesis that become hyperplastic in
adult life.
Histopath :
- predominance of hematopoietic cells with fewer fat cells, lymphoid aggregate & megakayocytes.
- because no radiographic specific finding, biopsy is indicated.

9. Soft tissue cyst of the neck
1) Branchial cyst:
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Located in the lateral portion of the neck anterior SCM muscle , or might appear in the
submandibular area .
There is an intraoral lymphoepithelial cyst counterpart
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Clinically: asymptomatic , usually become apparent in late childhood or young adulthood .
Histopathology : lined by stratified squamous epithelium ,pseudostratified squamous epithelium ,
or both . The epithelium is supported by CT containing lymphoid aggregate.
Differential Diagnosis : lymphadenitit, skin inclusion cyst, lymphangioma & parotid tumor.
Tx : surgical excision, the drainage from anterior margin of sternomastoid muscle.
2) dermoid cyst :
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When found on the oral cavity , it appears in the anterior portion of the floor of the mouth in the
Medline .
Etiology : entrapment of multipotential cells or implantation of epithelium.
Clinical features : when located above mylohyoid muscle displace tongue superiorly and posteriorly
& when located below it swelling of the neck occur at midline.
It is painless and slow growing .
On palpation, it is soft and doughy because of keratin and sebum in the lumen .
Histopath. : lined by stratified squamous epithelium , supported by fibrous connective tissue wall .
numerous secondary structure such as hair follicle , sweat gland and sebaceous gland are found .
Tx: surgical excision .
3) thyroglossal tract cyst :
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The basis of this lesion is related to thyroid gland development.
May occur from the posterior portion of the tongue to midline of the neck.
Occur in patient over 30 & less than 10 years.
Histopathology: above the hyoid bone ,the cyst lined by stratified squamous epithelium , below the
hyoid bone it is lined by columnar or ciliated epithelium .
Asymptomatic
Tx: surgical excision .