odontogenic cysts

Information about odontogenic cysts

Published on October 30, 2010

Author: drsundeepbhagwath

Source: authorstream.com


ODONTOGENIC CYSTS : ODONTOGENIC CYSTS Prepared by: - Dr Sundeep S Bhagwath OVERVIEW : OVERVIEW DEFINATION TYPES OF CYSTS PARTS OF A CYST CLASSIFICATION OF JAW CYSTS CLINICAL, RADIOLOGICAL, HISTOLOGICAL FEATURES AND DIFFERENTIAL DIAGNOSIS OF IMPORTANT JAW CYSTS. DEFINATION : DEFINATION Cyst is defined as a pathological cavity which may or may not be lined by epithelium and is filled with solid, semi solid or gaseous material but not pus. TYPES OF CYSTS : TYPES OF CYSTS TRUE CYSTS: that which is lined by epithelium e.g dentigerous cyst, radicular cyst etc. PSEUDO CYSTS: not lined by epithelium, e.g. Solitary bone cyst, Aneurismal bone cyst etc PARTS OF A CYST : PARTS OF A CYST Cyst has following parts: - WALL (made of connective tissue) - EPITHELIAL LINING - LUMEN OF CYST Slide 6: CLASSIFICATION OF JAW CYSTS: - 1. EPITHELIAL: - A. ODONTOGENIC: DEVELOPMENTAL INFLAMMATORY Odontogenic keratocyst - Radicular Dentigerous cyst - Residual Eruption cyst - Paradental Gingival cyst of infants Gingival cyst of adults Lateral periodontal cyst Calcifying odontogenic cyst Glandular odontogenic cyst Prepared by Dr Sundeep S Bhagwath Slide 7: B. NON ODONTOGENIC: - Nasopalatine duct cyst - Median palatine cyst - Nasolabial cyst - Globulomaxillary cyst II. NON EPITHELIAL CYST: - - Simple / solitary bone cyst - Aneurismal bone cyst - Stafne cyst ODONTOGENIC KERATOCYST : ODONTOGENIC KERATOCYST Slide 9: OKC is a cyst containing keratin and lined with keratinized epithelium. It arises from proliferation and cystic degeneration of cell rests of denta lamina. Keratocyst - Confusing term, since many times dentigerous and radicular cysts are also lined by keratinized epithelium. However, here, the keratinization is due to metaplasia induced by underlying connective tissue. Slide 10: CLINICAL FEATURES: - Age incidence: Any age, peak in 2nd & 3rd decades Sex incidence: More in males Site predilection: Mandible affected more. 50% cases occur in angle region and extend to ascending ramus and forwards to body of mandible. Slide 11: Signs & symptoms: Pain, swelling and discharge and occasionally, paresthesia of lower lip and teeth. Many times lesion enlarges so much that pathological fracture occurs. Occurs because OKC expands by spreading through medullary spaces, thereby reaching to a large size without expanding the cortical plates Expanding cyst can also cause tooth displacement. GORLIN-GOTZ SYNDROME : GORLIN-GOTZ SYNDROME Also called Nevoid-basal cell carcinoma-bifid rib syndrome. Syndrome composed of multiple odontogenic keratocysts, bifid ribs, frontal bossing and multiple nevoid basal cell carcinomas in the patient. Therefore in any case of multiple unerupted teeth, a panaromic X ray must be taken to rule out this syndrome. Slide 13: RADIOLOGICAL FEATURES:- Initially – small, round ‘lucency. Extensive lesions – well defined, scalloped, unilocular in most cases Scalloping due to unequal growth in different parts of cyst wall. Multilocular variety less common. OKC – RADIOGRAPHIC VARIETIES : OKC – RADIOGRAPHIC VARIETIES 1. REPLACEMENTAL – Cyst forms in place of normal tooth by degeneration of dental lamina. 2. EXTRANEOUS – OKC occurs in ascending ramus, away from tooth bearing areas Slide 15: 3. COLLATERAL – OKC occurs adjacent to root of tooth, mimicking a lateral periodontal cyst. 4. FOLICULAR KERATOCYST - Here, a developing tooth erupts into the lumen of overlying OKC. Slide 16: 5. ENVELOPMENTAL – This is an odontogenic keratocyst which embraces or envelopes an adjacent unerupted tooth. Slide 17: DIFFERENTIAL DIAGNOSIS: - In case of unilocular ‘lucencies – Dentigerous cyst, Eruption cyst, COC, AOT, Unicystic ameloblastoma etc. In case of multilocular ‘lucencies – Conventional ameloblastoma, CEOT, Central giant cell granuloma, Aneurysmal bone cyst etc. Slide 18: HISTOLOGICAL FEATURES: - In most cases, the cyst lining is thin, lined by a corrugated, parakeratinized stratified squamous epithelium, usually 5 – 8 cells thick without rete ridges. The basal cell layer has columnar / cuboidal cells with reversely polarized nuclei, imparting a “picket fence” or “tombstone” appearance. Slide 19: A histological variant of OKC – orthokeratinized cyst lining. In the connective tissue wall, many times, small islands of epithelium similar to overlying lining epithelial lining are seen. Some of these islands are small daughter / satellite cysts. Slide 21: COMPLICATIONS IN OKC: - 1.Malignant transformation of cyst lining – rare, but has been reported. 2. Recurrence – high rate of recurrence. REASONS FOR RECURRENCE – 1. Thin, fragile lining is very difficult to remove completely. 2. New cysts develop from satellite cysts left behind. 3. Some cysts may be left behind in cases of Gorlin – Gotz syndrome. 4. New cysts can also develop from basal cells of overlying oral epithelium, especially in ramus – 3rd molar region. Slide 22: TREATMENT: - The treatment of choice is MARSUPIALIZATION in case of extensive lesions lying dangerously close to vital anatomical structures. In small lesions enucleation and thorough curettage is preferred. DENTIGEROUS CYST : DENTIGEROUS CYST Slide 24: Defined as cyst originating after crown of a tooth is completely formed, by accumulation of fluid between reduced dental epithelium and tooth substance. Encloses crown of impacted / unerupted tooth and is attached to its neck. Slide 25: CLINICAL FEATURES: - Age incidence: 1st to 3rd decades. Sex incidence: Slight male predilection Site predilection: Always associated with crown of impacted / unerupted tooth, usually mandibular 3rd molar, maxillary canine and maxillary 3rd molars Frequency: Most common developmental odontogenic cyst. Prepared by Dr Sundeep S Bhagwath Slide 26: Signs & symptoms: Most cysts grow to a large size before being discovered accidentally while observing a dental x ray to detect the cause of an unerupted tooth. Large lesions can cause cortical expansion, leading to facial asymmetry, teeth displacement, root resorption, even pain, if infected. Prepared by Dr Sundeep S Bhagwath Slide 27: RADIOLOGICAL FEATURES: Manifests as unilocular, well defined, ‘lucency with sclerotic margins, associated with crown of impacted / unerupted tooth. A large DC may show persistence of boney trabeculae, giving the appearance of multilocularity. Prepared by Dr Sundeep S Bhagwath Slide 28: DIFFERENTIAL DIAGNOSIS: - Although it presents a unique feature, yet some lesions must be considered in its DD. 1. Unicystic ameloblastoma 2. Adenomatoid odontogenic tumor. Prepared by Dr Sundeep S Bhagwath Slide 29: HISTOLOGICAL FEATURES: - a. Non inflammed type: Lining derived from reduced dental epithelium, consists of 2-4 cell layers of non keratinized epithelium, without rete ridges. Wall composed of thin fibrous CT appearing immature, as it is derived from the dental papilla. Prepared by Dr Sundeep S Bhagwath Slide 31: b. Inflamed type: Lining shows varying degrees of hyperplasia with rete ridges and occasionally even keratinization. Wall is composed of mature CT which shows infiltration by chronic inflammatory cells. Focal areas of mucous cells can be seen in the lining. Small odontogenic epithelial islands can be seen in the wall. Prepared by Dr Sundeep S Bhagwath Slide 32: POTENTIAL COMPLICATIONS: - Recurrence due to incomplete surgical removal. Development of ameloblastoma either from lining epithelium or from odontogenic islands in the CT wall. Development of squamous cell carcinoma from same two sources. Development of mucoepidermoid carcinoma from mucus secreting cells in the lining. Prepared by Dr Sundeep S Bhagwath ERUPTION CYST : ERUPTION CYST Typical c/f of an eruption cyst. Note a bluish colored, dome shaped swelling over the unerupted molar. This cyst is nothing but a dentigerous cyst occurring in soft tissues, instead of bone. Prepared by dr Sundeep S Bhagwath GINGIVAL CYST OF ADULT : GINGIVAL CYST OF ADULT Slide 35: Uncommon cyst of gingival soft tissues. Occurs either on free or attached gingiva. Believed to be the soft tissue counterpart of the Lateral periodontal cyst. PATHOGENESIS: - Believed to arise from rests of dental lamina. Prepared by Dr Sundeep S Bhagwath Slide 36: CLINICAL FEATURES: - Age incidence: 5th and 6th decades. Sex incidence: Female predilection. Site predilection: Mandibular canine - premolar region. Prepared by Dr Sundeep S Bhagwath Slide 37: SIGNS & SYMPTOMS: - Slowly enlarging, well circumscribed painless swelling. Invariably occurs on facial aspect of free / attached gingiva. Surface of lesion is smooth and of normal color. Fluctuant lesion, adjacent teeth are vital Prepared by Dr Sundeep S Bhagwath Slide 38: DIFFERENTIAL DIAGNOSIS: - ALL GINGIVAL SWELLINGS (EPULIS) MUST BE CONSIDERED IN THE DD. Peripheral giant cell granuloma Pyogenic granuloma Peripheral ossifying fibroma Irritation fibroma Prepared by Dr Sundeep S Bhagwath Slide 39: HISTOLOGICAL FEATURES:- H/p features identical to Lateral periodontal cyst. Some cysts lined by thin, flattened stratified squamous epithelium. Sometimes, focal thickenings (Plaques) may be found within the lining. Prepared by Dr Sundeep S Bhagwath Slide 40: TREATMENT: - It is best treated by local surgical excision. Prepared by Dr Sundeep S Bhagwath LATERAL PERIODONTAL CYST : LATERAL PERIODONTAL CYST Slide 42: Uncommon, but well recognized type of odontogenic cyst. Designation of LPC restricted only to those cysts which occur in PDL region on lateral aspect of teeth and in which inflammatory etiology and a diagnosis of collateral OKC have been ruled out clinically and histologically Prepared by Dr Sundeep S Bhagwath Slide 43: CLINICAL FEATURES: - Age incidence: 20 – 60 years, peak in 6th decade. Sex incidence: Male predilection. Site predilection: Lateral PDL regions of mandibular premolars, followed by anterior maxilla. Prepared by Dr Sundeep S Bhagwath Slide 44: Signs & symptoms: Usually asymptomatic as it occurs on the lateral aspect of root of tooth. Occasionally pain and swelling may occur. Associated teeth are vital, unless otherwise affected. Cysts rarely < 1cm in size, except for BOTRYOID VARIETY which is larger and also a multilocular lesion. Prepared by Dr Sundeep S Bhagwath Slide 45: RADIOLOGICAL FEATURES: - Round to ovoid ‘lucency with sclerotic margins. Cyst can be present anywhere between cervical margin to root apex. Radiographically, it can be confused with collateral OKC. Prepared by Dr Sundeep S Bhagwath Slide 46: DIFFERENTIAL DIAGNOSIS: - Following lesions must be considered in radiological differential diagnosis- 1. Collateral OKC 2. Lateral radicular cyst (if associated tooth is non vital). Prepared by Dr Sundeep S Bhagwath Slide 47: PATHOGENESIS: - Similar to the Gingival cyst of adults, this cyst too is believed to arise from the rests of dental lamina. Prepared by Dr Sundeep S Bhagwath Slide 48: HISTOLOGICAL FEATURES:- Most commonly lined by a thin, non keratinized epithelium. If lining appears keratinized diagnosis of collateral OKC is given. Many regions of lining may show focal epithelial thickenings (PLAQUES). Small epithelial nests may be seen in CT wall, which may show signs of mild inflammation. Prepared by Dr Sundeep S Bhagwath Slide 49: TREATMENT: - Small cysts are treated by complete surgical enucleation. Larger, especially botryoid variety must be carefully followed after enucleation to watch for recurrence. Prepared by Dr Sundeep S Bhagwath CALCIFYING ODONTOGENIC CYST : CALCIFYING ODONTOGENIC CYST Slide 51: Also called as Odontogenic ghost cell cyst or Gorlin cyst. Has many features of odontogenic tumor, therefore it is placed in the category of tumors in the latest WHO classification of odontogenic cysts and tumors. Prepared by Dr Sundeep S Bhagwath Slide 52: CLINICAL FEATURES: - Age incidence: Wide range, peak in 2nd decade. Sex incidence: Equal. Site predilection: Anterior segment of both jaws. Prepared by Dr Sundeep S Bhagwath Slide 53: Signs & symptoms: Swelling is the commonest complaint, seldom associated with pain. Intraosseous lesions can cause hard bony expansion and resulting facial asymmetry. Displacement of teeth can also occur. Prepared by Dr Sundeep S Bhagwath Slide 54: RADIOLOGICAL FEATURES:- Intraosseous lesions produce well defined ‘lucency which is usually unilocular. Irregular calcified masses of varying sizes may be seen within the ‘lucency. Displacement of root/roots with or without root resorption and expansion of cortical plates also seen. Prepared by Dr Sundeep S Bhagwath Slide 55: DIFFERENTIAL DIAGNOSIS: - Based on radiographic appearance, following lesions must be included in the provisional diagnosis – Ameloblastoma CEOT AOT Ameloblastic fibro odontoma Slide 56: PATHOGENESIS: - COC is a unicystic process and develops from the reduced dental epithelium or remnants of dental lamina. The cyst lining has the potential to induce formation of dentinoid or even odontoma in adjacent CT wall. Prepared by Dr Sundeep S Bhagwath Slide 57: CLASSIFICATION: - Type 1 A – Simple unicystic type Type 1 B – Odontome producing type Type 1 C – Ameloblastomatous proliferating type Type 2 – NEOPLASM, separate entity Prepared by Dr Sundeep S Bhagwath Slide 58: HISTOLOGICAL FEATURES: - Lining is usually thin about 6 – 8 cell thick, may be thickened in other areas. Lining shows characteristic odontogenic features with reversely polarized basal cell layer. TYPICALLY – GHOST CELLS may be seen in thicker areas of lining. Prepared by Dr Sundeep S Bhagwath Slide 59: Ghost cells are enlarged, ballooned, ovoid, eosinophilic cells with well defined cell boundaries. Some times many cells may fuse. They represent abnormal keratinization and frequently calcify. Tubular dentinoid and even complex odontome may be found in CT wall close to epithelial lining. Prepared by Dr Sundeep S Bhagwath Slide 60: TREATMENT: - Treatment of choice is surgical enucleation, unless it is associated with other odontogenic tumors like odontoma. In such cases, wider excision is required. Prepared by Dr Sundeep S Bhagwath RADICULAR CYST : RADICULAR CYST Slide 62: Also called APICAL PERIODONTAL CYST. By definition, a radicular cyst arises from epithelial rests of Malassez located in the PDL as a result of inflammation. Often, radicular cyst remains behind in jaws after removal of infected tooth – then called RESIDUAL CYST. Prepared by Dr Sundeep S Bhagwath Slide 63: CLINICAL FEATURES: - Age incidence: peak in 3rd, 4th and 5th decades. Sex incidence: Slightly more in males. Site predilection: Maxillary anterior region. Frequency: Commonest cystic lesion of jaws. Prepared by Dr Sundeep S Bhagwath Slide 64: Signs & symptoms: Primarily symptom less. Discovered accidentally during routine dental X ray exam. Slowly enlarging hard bony swelling initially. Later, if cysts breaks through cortical plates, lesion becomes fluctuant. Diagnostic criteria – associated teeth are non vital Rare in deciduous teeth. Prepared by Dr Sundeep S Bhagwath Slide 65: RADIOLOGICAL FEATURES: Classically presents as round / ovoid ‘lucency with sclerotic borders and associated with pulpally affected tooth / teeth. If infection supervenes, the margins become indistinct, making it impossible to distinguish it from a peripaical granuloma. Prepared by Dr Sundeep s Bhagwath Slide 66: DIFFERENTIAL DIAGNOSIS: - Following lesions must be distinguished from other periapical radiolucencies– 1. Periapical granuloma 2. Peripaical cemento – osseous dysplasia (early lesions) Prepared by Dr Sundeep S Bhagwath Slide 67: PATHOGENESIS: - 1. PHASE OF INITIATION: Accepted generally that rests of Malassez included within a developing periapical granuloma proliferates to form the lining of radicular cyst. How these cells are stimulated is not clear. Some product of non vital pulp can be responsible which simultaneously evokes an inflammatory response in CT. Immune factors also held responsible as plenty of plasma cells are seen in a periapical granuloma. Prepared by Dr Sundeep S Bhagwath Slide 68: PHASE OF INITITIATION Slide 69: 2.PHASE OF CYST FORMATION: Can occur in two possible ways. One theory states that epithelium proliferates and covers the bare CT surface of the abscess cavity. Another theory – cyst cavity forms within proliferating epithelium as the cells in center move away from their nutrient source. Prepared by Dr Sundeep S Bhagwath Slide 70: PHASE OF CYST FORMATION Slide 71: 3. PHASE OF ENLARGEMENT: - Enlargement occurs by collection of fluid within the lumen of the cyst. Osmosis plays an important role here as the cyst wall appears to have the properties of a semi permeable membrane. Prepared by Dr Sundeep S Bhagwath Slide 72: HISTOLOGICAL FEATURES:- Lined partly / completely by non keratinized epithelium of varying thickness. Epithelium usually shows arcading around the CT. The CT wall shows inflammatory infiltrate mainly in the form of lymphocytes and plasma cells. Prepared by Dr Sundeep S Bhagwath Slide 73: Hyaline / Rushton bodies are found in epithelium and rarely in CT wall. These are curved or linear structures with eosinophilic staining properties. Prepared by Dr Sundeep S Bhagwath Slide 74: Cholesterol crystals in from of clefts are often seen in the CT wall, inciting a foreign body giant cell reaction. Originate from disintegrating RBC’s in presence of inflammation. Different types of dystrophic calcification are also seen in CT wall. Prepared by Dr Sundeep S Bhagwath Slide 75: Mucus cell metaplasia as well as respiratory cells may be seen in the epithelial lining. Keratinization if found is due to metaplasia and must not be confused with an OKC. Prepared by Dr Sundeep S Bhagwath RESIDUAL CYST : RESIDUAL CYST Radiographic appearance of a large residual cyst left behind after extraction of 1st mandibular molar. Prepared by Dr Sundeep S Bhagwath NASOPALATINE DUCT CYST : NASOPALATINE DUCT CYST Slide 78: Also classified as “FISSURAL CYSTS”. Believed to be derived from epithelial remnants included during closure of embryonic facial processes. Controversy – actual “closure” of embryonic processes does not occur. Grooves between processes is smoothed by proliferation of underlying mesenchyme. Usually occurs within the nasopalatine canal or in soft tissue of palate at the opening of canal. Slide 79: CLINICAL FEATURES: - Age incidence: 4th, 5th & 6th decades. Sex incidence: More in females Frequency: Commonest non odontogenic developmental cyst Prepared by Dr Sundeep S Bhagwath Slide 80: Signs & symptoms: Commonest symptom is swelling, usually in anterior region of mid palate. Swelling can also occur in midline on labial aspect of alveolar ridge. If pressure on NP nerves – pain Exclude possibility of periapical cyst by testing vitality of incisors. Prepared by Dr Sundeep S Bhagwath Slide 81: RADIOLOGICAL FEATURES: - Seen as ‘lucency usually in incisive canal – DIFFICULT TO DISTINGUISH FROM A NATURALLY LARGE INCISIVE CANAL. “lucency with AP dimension upto 10 mm considered as enlarged incisive canal, but if “lucency < 14 mm, then NP duct cyst. The “lucency appears well defined with sclerotic borders, in midline of palate between roots of incisors. Prepared by Dr Sundeep S Bhagwath Slide 83: DIFFERENTIAL DIAGNOSIS: - Radicular cyst, if it is associated with a pulpally involved tooth. Large incisive canal. Slide 84: PATHOGENESIS: - In lower animals, the NP duct concerned with olfactory sensation – in humans only vestigial remnants persist in incisive cana in form of epithelial islands, ducts, cords etc. These nests can show central degenration to form cysts. Etiology for cyst transformation is yet unclear. Some believe, it may arise spontaneously like an OKC. Prepared by Dr Sundeep S Bhagwath Slide 85: HISTOLOGICAL FEATURES: - Lining epithelium extremely variable, consisting of stratified squamous, pseudo stratified columnar, simple columnar or cuboidal epithelium. Most commonly lining is stratified squamous followed by pseudo stratified columnar. A useful diagnostic aid – presence of large nerve and vascular bundles in CT wall. Prepared by Dr Sundeep S Bhagwath Slide 87: TREATMENT: - Simple surgical enucleation is the treatment of choice. Prepared by Dr Sundeep S Bhagwath NASOLABIAL CYST : NASOLABIAL CYST Slide 89: Also called as Nasoalveolar cyst. Occurs outside the bone in nasolabial fold below the ala nasi. The alveolar bone is not involved, therefore “Nasolabial cyst” is the more preferred term. Prepared by Dr Sundeep S Bhagwath Slide 90: CLINICAL FEATURES: - Age incidence: Peak incidence in 4th & 5th decades. Sex incidence: More in females. Frequency: Rare in occurrence. Prepared by Dr Sundeep S Bhagwath Slide 91: Signs & symptoms: Commonest complaint – slowly growing swelling and occasionally, pain and difficulty in nasal breathing. Extra orally – filling out of nasolabial fold and may lift ala nasi. Intra orally – bulge in labial sulcus. Fluctuant lesion. Prepared by Dr Sundeep S Bhagwath Slide 92: RADIOLOGICAL FEATURES: - Difficult to interpret on radiograph. May be seen as localized increased ‘lucency of alveolar process above apices of incisors. ‘Lucency results from pressure resorption on labial surface of maxilla. Prepared by Dr Sundeep S Bhagwath Slide 93: PATHOGENESIS: - Believed to develop from lower anterior portion of nasolacrimal duct. When margins of lateral and maxillary processes fuse, ectoderm along boundary between them gives rise to solid cellular rod which first develops as a linear surface elevation (Nasolacrimal ridge) and then sinks into underlying mesenchyme. Slide 94: This solid rod canalizes to form NL duct. The NL cysts are located such that it is possible that they develop from embryonic remnants of NL duct. Importantly, a mature NL duct is lined by pseudo stratified columnar epithelium, which is also the lining of NL cyst. Slide 95: HISTOLOGICAL FEATURES: Cyst lined by non ciliated pseudo stratified columnar epithelium. Goblet cells also seen in some cases. Occasionally, part of lining may be cuboidl / flat squamous. CT wall is fibrous, relatively acellular with fibers arranged loosely or compactly. Prepared by Dr Sundeep S Bhagwath GLOBULOMAXILLARY CYST : GLOBULOMAXILLARY CYST Slide 97: Cyst is found within bone between roots of maxillary lateral incisor and canine diverging their roots. Current evidence – NOT A FISSURAL CYST. Earlier believed to arise from non odontogenic epithelium entrapped at site of fusion of globular process of fronto nasal process and maxillary process. Prepared by Dr Sundeep s Bhagwath ANEURYSMAL BONE CYST : ANEURYSMAL BONE CYST Slide 99: Uncommon cyst, found mostly in long bones and spine. CLINICAL FEATURES: - Age incidence: First 3 decades. Sex incidence: Mainly females. Site predilection: molar regions of mandible & maxilla. Signs & symptoms: Hard, rapidly growing swelling which can cause malocclusion. If lesion perforates cortical plates, can cause “egg shell crackling”. Prepared by Dr Sundeep S Bhagwath Slide 100: RADIOLOGICAL FEATURES: Classically seen as a unilocular, ovoid / fusiform ‘lucency which balloons the cortical plates. Teeth displacement and root resorption also observed. Prepared by Dr Sundeep S Bhagwath Slide 101: DIFFERENTIAL DIAGNOSIS: Conventional ameloblastoma CEOT Central giant cell granuloma Slide 102: PATHOGENESIS: - Controversy whether lesion arises de novo or from a vascular disturbance in the form of sudden venous occlusion or development of an AV shunt occurring secondarily in a pre existing lesion like central giant cell granuloma, Osteosarcoma etc. Due to the malformation, change in hemodynamic forces occurs which can lead to ABC. Prepared by Dr Sundeep S Bhagwath Slide 103: HISTOLOGICAL FEATURES: Lumen not lined by epithelium. Wall composed of many capillaries and blood filled spaces, separated by delicate loose CT. Many small multinucleated giant cells and trabeculae of osteoid / woven bone. Many times features of fibrous dysplasia, Ossifying fibroma also seen Prepared by Dr Sundeep S Bhagwath SIMPLE / SOLITARY BONE CYST : SIMPLE / SOLITARY BONE CYST Slide 105: Also called as Hemorrhagic bone cyst, or Traumatic bone cyst. Commonly seen in mandible, rare in maxilla. Identical to solitary bone cyst of humerus in children and adolescents. Prepared by Dr Sundeep S Bhagwath Slide 106: CLINICAL FEATURES: - Age incidence: Young individuals Sex incidence: Equal Site predilection: Body and symphysismenti of mandible. Prepared by Dr Sundeep S Bhagwath Slide 107: Signs & symptoms: Asymptomatic. Rarely, swelling and pain may be seen. Half of all patients give a history of trauma to the area. Prepared by Dr Sundeep S Bhagwath Slide 108: RADIOLOGICAL FEATURES: - Appears as a ‘lucency with irregular but well defined edges and slight cortication. On occlusal view the ‘lucency is seen to extend along cancellous bone. Prepared by Dr Sundeep S Bhagwath Slide 109: PATHOGENESIS: - None of the theories are certain about exact cause. First theory – cyst may follow trauma to bone which causes intra medullary hemorrhage which fails to organize. This clot subsequently liquefies - CYST. Recent theory –n osteogenic cells fail to differentiate locally and thus instead of bone, the undifferentiated cells form synovial tissue. Prepared by Dr Sundeep S Bhagwath Slide 110: HISTOLOGICAL FEATURES:- Lumen not lined by any epithelium (Pseudo cyst). Wall shows loose fibro vascular CT. Hemorrhage and hemosiderin pigment usually present. Multinucleated giant cells scattered within the CT. Adjacent bone shows osteoclastic resorption on inner surface. Slide 111: TREATMENT: - Cyst aspirated first and then opened and packed. Patient is kept under observation. Cyst usually regresses on its own. Prepared by Dr Sundeep S Bhagwath BIBLIOGRAPHY : BIBLIOGRAPHY Soames JV, Southam JC. Oral pathology/. 3rd ed. Oxford 2002. Shafer WG, Hine MK, Levy BM. A text book of oral pathology. 6th ed. W.B. Saunders Company. Phil, London, Toronto, 2005. Neville BW, Damm DD, Allen CM, Bouquot JE. Oral and maxillofacial pathology. 2nd ed. WB Saunders Company. Phil, London, Toronto, 2007. Regezi JA, Sciubba JJ, Jordan RCK. Oral pathology: Clinical Pathologic Correlations. 4th ed. Saunders Company, 2003. ACKNOWLEDGEMENT : ACKNOWLEDGEMENT All pictures in this presentation are courtesy of authors mentioned in the bibliography and the following authors also: Color Guide Oral Pathology. R A Cawson, F W Odell. 1st ed. Churchill Livingstone, New York. Neville’s color atlas of clinical Oral Pathology, 2nd edition. Slide 114: THANK YOU FOR YOUR PATIENCE !

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