لخّصلي

Definition Cyst is a pathological cavity lined by epithelium and containing fluid or semi fluid material.Displacement of teeth , with facial asymmetry is common .Cystic content : keratin , yellowish or dirty white material similar to pus without offensive odor.Radiographic features : multilocular , radiolucent area with typical " soap - bubble appearance " scalloping border .Histopathological features : Parakeratinized odontogenic cyst ? Cystic cavity lined by keratinized stratified odontogenic epithelium , with no rete peg ? basal epithelial layer is made up of tall , columnar cells , 6-10 cells in thickness , showing palisading arrangement ( tombstone ) o Epithelium is thin , folded and loosely attached to the underlying connective tissue . ? Mitotic activity is frequent . ? Keratin shows remnants of nuclei ( parakeratinized ).Histopathologic Features Surface corrugated with a parakeratotic surface thin , regular , continuous layer of st . sq . ep . 6-8 cells thick & smooth b.m.Histopathological features : ? The WHO : parakeratinizing keratocyst the keratocystic odontogenic tumor cystic lumen shows a corrugated ( uneven ) appearance and contains keratin connective tissue stroma is thin , few inflammatory cells . -Connective tissue wall shows small islands of epithelium similar to the lining epithelium ( daughter or satellite cysts ). Ortho - keratinized primordial cyst Less common than parakeratinized type ( 15 % ) Less aggressive o Lower recurrence rate The surface is smooth ( non - corrugated ) Subsurface layer of granular cells o Basal cell less prominent.recurrence rate is very high ( due to the presence of daughter cysts , the loose attachment between epithelium and connective tissue ; and the high mitotic activity ) OKC has been found to be associated with nevoid basal cell carcinoma syndrome . Dentigerous Cyst ( Follicular Cyst ) : ? Cyst that encloses the crown of an impacted tooth at its neck portion . o arises due to fluid accumulation between reduced enamel epithelium and enamel surface resulting in a cyst in which the crown is located within the lumen . Enlargement is slower than periodontal or primordial cyst due to lower mitotic index = number of mitosis per length of epithelium ).Dentigerous Cyst ( Follicular Cyst ) : Radiological features : ? well defined , unilocular , radiolucent area , enclosing the crown of an impacted tooth , and the periphery of the lesion is bordered by a radiopaque margin . Radiological types seen are : central , lateral and circumferential types .Histopathological Features : Presence of cystic cavity , lined by a thin layer of odontogenic epithelium , supported by a connective tissue stroma . cystic epithelial cells are usually flat or cuboidal , epithelium is nonkeratinized . o Mucous cells may be seen within the lining epithelium . Complications of dentigerous cyst Jaw fracture Can give rise to ameloblastoma Malignant transformation into mucopeidermoid or squamous cell carcinoma. Eruption cyst Superficial dentigerous cyst . A soft tissue cyst that arise from enamel organ epithelium after enamel formation . Age : children o Site : unerupted deciduous teeth or permanent molar Appearance : soft round bluish swelling X - ray : negative.Keratinizing and / or calcifying epithelial odontogenic cyst ( Gorlin cyst ) o It is a relatively uncommon odontogenic cystic lesion of the jaw bones . ? There are three variants of this : Solid , cystic , neoplastic o ( 75 % of cysts are intraosseous , 25 % extraosseous ) Clinical features : The cyst develops in the second decade of age ; occurring in the anterior part of maxilla and mandible . Bony , hard swelling of the jaw with expansion and distortion of cortical plates and displacement of regional teeth .KCOC Radiological features : - Shows a unilocular or multilocular radiolucent area with a well - corticated margin . o - Multiple , small , radiopaque calcified foci , of varying radiodensity are found .KCOC Histopathological features : ? - A cystic cavity lined by an odontogenic , keratinized epithelium ; the cells are columnar or cuboidal showing a palisading arrangement . -Basal cell nuclei are darkly stained and polarized away from basement membrane -Above the basal layer , there is a layer of loosely arranged epithelial cells resembling the stellate reticulum cells Some epithelial cells may proliferate to fill the cystic lumen lumen , giving the cyst the picture of a solid neoplasm.Cystic epithelium shows the presence of many " ghost cells " Ghost cells : a ) swollen , have hyaline eosinophilic cytoplasm , ill defined outline , their nuclei undergo karyolysis b ) may become keratinized or calcified Irregular eosinophilic masses of dentinoid matrix are seen within the epithelium Calcified bodies : multiple , small , basophilic , seen within the epithelial lining of the cyst .Toxins exit from apex Periapical inflammation , apical periodontitis , periapical granuloma Stimulation ( inflammatory hyperplasia ) of epithelial rests of Malassez Epithelial mass increases in size and its central area undergoes liquefaction necrosis caused by a lack of blood supply This creates an epithelial lined cavity filled with fluid , i.e. Granuloma become a cyst .Mechanism of cyst enlargement |Classification of Cysts Shear's Classification: Cysts of the jaws: A. Epithelium : odontogenic:* developmental: Primordial, Gingival cyats of Infants, Gingival cysts of adulte, Lateral periodontal ,Dentigorous ,Eruption cysts ,Calcifying odontogenic cyst .*inflammation: radical , reaidual , paradental cyst .ODONTOGENIC CYSTS : These are cysts in which the epithelial lining of the lumen is derived from epithelial rests of tooth - forming tissue , such as : a- Epithelial rests of Malassez b- Reduced enamel epithelium c - Remnants of dental lamina ( epithelial rests of Serres ) .Inflammatory periapical cyst( radicular cyst):Clinical features -Smaller lesions are asymptomatic -Larger cysts produce slow , enlarging , bony hard swelling of the jaw , expansion and distortion of cortical plates .3.Cysts of soft tissues of mouth , face and neck: Dermoid and epider- mold cyst ,Branchial cyst ,Thyroglossal duct cyst, Cystic hygroms Cysts of salivary glands ,Parnaitic / hydatid cysts.2 - osmotic pressure within the cyst becomes higher than hydrostatic pressure , causing fluid transport across the epithelial lining and C.T. , from outside to inside the cystic cavity 3- Cystic growth will stimulate osteoclatic activity & bone resorption 4- Inflammatory mediators ( prostaglandin ) stimulate bone resorption.a small cystic cavity , lined by non keratinized stratified squamous epithelium , 1-5 cell layers thick ( resembles reduced enamel epithelium ) with focal thickenings .The Botryoid odontogenic cyst is a polycystic variant of the lateral periodontal cyst , resembling a cluster of grapes.Clinical features : ?2.1.??

Definition Cyst is a pathological cavity lined by epithelium and containing fluid or semi fluid material.
Classification of Cysts Shear's Classification:
Cysts of the jaws: A. Epithelium : odontogenic:* developmental: Primordial, Gingival cyats of Infants, Gingival cysts of adulte, Lateral periodontal ,Dentigorous ,Eruption cysts ,Calcifying odontogenic cyst .*inflammation: radical , reaidual , paradental cyst . * Non Odontogenic : nasopalatine, Median paratino , alveolar , mandibular ,Globulomaxillary ,Nasolabial.
b. Non epithelium : Simple bone cysts, Traumatic bone cyst , Bolitary bone oyst ,Homorrhagic bone cyst ,Anourysmal bone cyst.
2. cyst of maxillary antrum:Denign mucosal cynt of maxillary antrum, Surgical cittatad cyst of the Maxilla.
3.Cysts of soft tissues of mouth , face and neck: Dermoid and epider- mold cyst ,Branchial cyst ,Thyroglossal duct cyst, Cystic hygroms Cysts of salivary glands ,Parnaitic / hydatid cysts.
Classification : I- Odontogenic cysts 2- Non- Odontogenic cysts 3- Pseudocysts 4- Soft tissue cysts.
ODONTOGENIC CYSTS : These are cysts in which the epithelial lining of the lumen is derived from epithelial rests of tooth - forming tissue , such as : a- Epithelial rests of Malassez b- Reduced enamel epithelium c - Remnants of dental lamina ( epithelial rests of Serres ) .

1. Radicular Cyst ( inflammatory Periapical periodontal cyst ) : -The most common type of odontogenic cysts -occurs in relation to apex of a nonvital tooth . -Necrosis of the pulp . Toxins exit from apex Periapical inflammation , apical periodontitis , periapical granuloma Stimulation ( inflammatory hyperplasia ) of epithelial rests of Malassez Epithelial mass increases in size and its central area undergoes liquefaction necrosis caused by a lack of blood supply This creates an epithelial lined cavity filled with fluid , i.e. Granuloma become a cyst .Mechanism of cyst enlargement | - necrotic cells present in cyst lumen cause an increase in osmotic pressure of the cyst fluid , due to breakdown of large protein molecules into smaller ones . 2 - osmotic pressure within the cyst becomes higher than hydrostatic pressure , causing fluid transport across the epithelial lining and C.T. , from outside to inside the cystic cavity 3- Cystic growth will stimulate osteoclatic activity & bone resorption 4- Inflammatory mediators ( prostaglandin ) stimulate bone resorption.
   Residual cyst ⚫when the involved tooth is extracted , the remaining cystic cavity is seen within the bone.Clinical features : - < males < 3rd , 4th , 5th decade of life . - < maxilla 4 - Rare in primary dentition . -The involved tooth : caries , fracture or discoloration .
   Inflammatory periapical cyst( radicular cyst):Clinical features -Smaller lesions are asymptomatic -Larger cysts produce slow , enlarging , bony hard swelling of the jaw , expansion and distortion of cortical plates . Later on , severe bone destruction by the cystic lesion may produce " egg - shell crackling " when digital pressure is applied to the bone . When part of bone is completely resorbed , a fluctuant bluish swelling is seen beneath the mucosa -If infection occurs , cyst is painful & rapidly growing.Radiological features : Peri - apical round or oval radiolucancy of variable size which is generally well delineated with a marked radiopaque rim . If the cyst is rapidly enlarging or infected , the outline becomes hazy ( due to increased vascularity and bone resorption ).Histopathological features Presence of a cystic cavity , lined by stratified squamous epithelium Lining is backed by a well - vascularized , connective tissue stroma . 4 The epithelium : non keratinized , In newly formed cyst : epithelium is hyperplastic , with localized areas of edema . Epithelium may be interrupted over areas of intense inflammation In fully formed cysts : epithelium is regular and flat .Inflammatory periapical cyst Histopathology Connective tissue : fibroblasts , collagen fibers , focal or diffuse inflammatory cells ( especially in newly formed cyst ) . Polymorphnuclear leucocytes are seen near epithelium Plasma cells and lymphocytes are seen in deeper areas . Russel bodies collection of immunoglobulins secreted by plasma cells . Foam cells ( lipid filled macrophages ) Cholesterol clefts . Multinucleated giant cells ( located near cholesterol clefts ) - Sources of cholesterol in cyst are -A ) cell membrane of RBCs B ) serum lipids C ) epithelial lining.Cyst wall lined by respiratory epithelium.Inflammatory periapical cyst Histopathology Connective tissue : fibroblasts , collagen fibers , focal or diffuse inflammatory cells ( especially in newly formed cyst ) . Polymorphnuclear leucocytes are seen near epithelium Plasma cells and lymphocytes are seen in deeper areas . Russel bodies collection of immunoglobulins secreted by plasma cells . Foam cells ( lipid filled macrophages ) Cholesterol clefts . Multinucleated giant cells ( located near cholesterol clefts ) - Sources of cholesterol in cyst are - A ) cell membrane of RBCs B ) serum lipids C ) epithelial lining.Histopathological features • Rushton bodies : eosinophilic hyaline bodies , tiny , linear , hairpin or arc shaped shaped bodies , unique to odontogenic cysts • • Origin of Rushton bodies : a ) Thrombus formation in small capillaries B ) type of keratin or enamel cuticle ⚫ -Dystrophic calcification may be found in epithelium or connective tissue .Variations in cyst lining include • respiratory epithelium , pseudostratified columnar ciliated with goblet cells ( especially in cysts located near the maxillary sinus or nasal cavity ) , OR undifferentiated embryonic epithelium Epithelium may become keratinized ( ortho or para keratinized ).Treatment : RCT and apical curettage - smaller cysts . Enucleation and marsupialization - larger cysts .
   Paradental cyst Type of odontogenic cyst that arise due to inflammation of soft tissue around partially erupted tooth More common in in mandibular 3rd molar Tooth : vital X - ray : negative Histology : resemble inflammatory periapical cyst , with intense inflammation in C.T. • Ttt : enucleation.
   Lateral Periodontal Cyst : Definition : Nonkeratinized , noninflammatory developmental cysts located adjacent or lateral to the root of a vital tooth between the alveolar crest and the root apex . It is derived from rests of dental lamina .Clinical features : < adult males < in mandibular premolar region , but also seen in maxillary and mandibular anterior region . Mostly asymptomatic ; but may exhibit a small , painless , soft tissue swelling . • The tooth associated with the cyst is vital .Radiological features : small , unilocular , " teardrop - shaped " radiolucent area , on the lateral aspect of the tooth root , Icm in diameter . surrounded by a thin , sclerotic margin .Histopathological features : ⚫ a small cystic cavity , lined by non keratinized stratified squamous epithelium , 1-5 cell layers thick ( resembles reduced enamel epithelium ) with focal thickenings . Cystic epithelium contains clusters of clear cells , with vacuolated cytoplasm . backed by a connective tissue wall.
   The Botryoid odontogenic cyst is a polycystic variant of the lateral periodontal cyst , resembling a cluster of grapes. .Histopathologic Features: Stratified squamous epithelium , thin ( 1 or 2 layers of cells ) .epithelial cells show clear cytoplasm , small deeply staining nuclei.
   Dental lamina cyst of the New born ( Gingival Cyst of New born ) Definition : Multiple , small , white nodules seen on the alveolar ridge of newborn , arising from remnant of the dental lamina . ⚫ Histopathology : A small , keratin - filled cystic cavity lined by a thin epithelium . Treatment : These cysts spontaneously rupture . No treatment is required . •when similar cysts may occur in the palate of newborn , they are called Epstein pearls if occurring in the midline , OR Bohn's nodules if scattered in hard / soft palate . Epstein pearls and Bohn's nodules are developmental non - odontogenic cysts , filled with keratin , having thin epithelial lining and are usually self- healing within months.
   Gingival Cyst of the Adult : soft tissue cyst , occurring in either the free or attached gingiva . arises from rests of dental lamina and represents the extraosseous counterpart of the lateral periodontal cyst . Clinical features : ⚫ occurs at any age but common in adults . Small , well - circumscribed , painless swelling of the gingiva Same colour as the adjacent normal mucosa Less than 1 cm in diameter .
   Odontogenic Keratocyst ( Primordial Cyst ) جايه ⚫ Definition : Developmental odontogenic cyst with aggressive clinical behavior and high recurrence rate . • Clinical features : - Mostly 2nd or 3rd decade of life . • < in the ramus area of the mandible . • • Usually asymptomatic . Lesions in the advanced stages , cause swelling of the jaw with expansion and distortion of the cortical plates . Displacement of teeth , with facial asymmetry is common .Cystic content : keratin , yellowish or dirty white material similar to pus without offensive odor.Radiographic features : multilocular , radiolucent area with typical " soap - bubble appearance " scalloping border .Histopathological features : Parakeratinized odontogenic cyst ⚫ Cystic cavity lined by keratinized stratified odontogenic epithelium , with no rete peg ⚫ basal epithelial layer is made up of tall , columnar cells , 6-10 cells in thickness , showing palisading arrangement ( tombstone ) • Epithelium is thin , folded and loosely attached to the underlying connective tissue . ⚫ Mitotic activity is frequent . ⚫ Keratin shows remnants of nuclei ( parakeratinized ).Histopathologic Features Surface corrugated with a parakeratotic surface thin , regular , continuous layer of st . sq . ep . 6-8 cells thick & smooth b.m.Histopathological features : ⚫ The WHO : parakeratinizing keratocyst the keratocystic odontogenic tumor cystic lumen shows a corrugated ( uneven ) appearance and contains keratin connective tissue stroma is thin , few inflammatory cells . -Connective tissue wall shows small islands of epithelium similar to the lining epithelium ( daughter or satellite cysts ).
   Ortho - keratinized primordial cyst Less common than parakeratinized type ( 15 % ) Less aggressive • Lower recurrence rate The surface is smooth ( non - corrugated ) Subsurface layer of granular cells • Basal cell less prominent.recurrence rate is very high ( due to the presence of daughter cysts , the loose attachment between epithelium and connective tissue ; and the high mitotic activity ) OKC has been found to be associated with nevoid basal cell carcinoma syndrome .
   Dentigerous Cyst ( Follicular Cyst ) : ⚫ Cyst that encloses the crown of an impacted tooth at its neck portion . • arises due to fluid accumulation between reduced enamel epithelium and enamel surface resulting in a cyst in which the crown is located within the lumen . Enlargement is slower than periodontal or primordial cyst due to lower mitotic index = number of mitosis per length of epithelium ).Dentigerous Cyst ( Follicular Cyst ) : Radiological features : ⚫ well defined , unilocular , radiolucent area , enclosing the crown of an impacted tooth , and the periphery of the lesion is bordered by a radiopaque margin . Radiological types seen are : central , lateral and circumferential types .Histopathological Features : Presence of cystic cavity , lined by a thin layer of odontogenic epithelium , supported by a connective tissue stroma . cystic epithelial cells are usually flat or cuboidal , epithelium is nonkeratinized . • Mucous cells may be seen within the lining epithelium . Complications of dentigerous cyst Jaw fracture Can give rise to ameloblastoma Malignant transformation into mucopeidermoid or squamous cell carcinoma.
   Eruption cyst Superficial dentigerous cyst . A soft tissue cyst that arise from enamel organ epithelium after enamel formation . Age : children • Site : unerupted deciduous teeth or permanent molar Appearance : soft round bluish swelling X - ray : negative.Keratinizing and / or calcifying epithelial odontogenic cyst ( Gorlin cyst ) • It is a relatively uncommon odontogenic cystic lesion of the jaw bones . ⚫ There are three variants of this : Solid , cystic , neoplastic • ( 75 % of cysts are intraosseous , 25 % extraosseous ) Clinical features : The cyst develops in the second decade of age ; occurring in the anterior part of maxilla and mandible . Bony , hard swelling of the jaw with expansion and distortion of cortical plates and displacement of regional teeth .KCOC Radiological features : - Shows a unilocular or multilocular radiolucent area with a well - corticated margin . • - Multiple , small , radiopaque calcified foci , of varying radiodensity are found .KCOC Histopathological features : ⚫ - A cystic cavity lined by an odontogenic , keratinized epithelium ; the cells are columnar or cuboidal showing a palisading arrangement . -Basal cell nuclei are darkly stained and polarized away from basement membrane -Above the basal layer , there is a layer of loosely arranged epithelial cells resembling the stellate reticulum cells Some epithelial cells may proliferate to fill the cystic lumen lumen , giving the cyst the picture of a solid neoplasm.Cystic epithelium shows the presence of many " ghost cells " Ghost cells : a ) swollen , have hyaline eosinophilic cytoplasm , ill defined outline , their nuclei undergo karyolysis b ) may become keratinized or calcified Irregular eosinophilic masses of dentinoid matrix are seen within the epithelium Calcified bodies : multiple , small , basophilic , seen within the epithelial lining of the cyst . - Connective tissue capsule , contains many " satellite " microcysts , ghost cells , multinucleated giant cells and dystrophic calcification.