BDS10010 Cystic Lesions of Bone (1) PDF

BDS10010 Cystic Lesions of Bone (1) Aims: The aim of this lecture is to detail the radiological and histopathological features of common odontogenic cystic lesions of the jaws. Objectives:  On completion of this lecture, the student should be able to:  Understand the radiological and histopatho...

BDS10010 Cystic Lesions of Bone (1) Aims: The aim of this lecture is to detail the radiological and histopathological features of common odontogenic cystic lesions of the jaws. Objectives:  On completion of this lecture, the student should be able to:  Understand the radiological and histopathological features of common odontogenic cystic lesions of the jaws  Have an appreciation that radicular cysts are the most common of all cystic lesions of the jaws A cyst is an epithelial lined pathologic cavity occurring in either hard or a soft tissue and may contain a fluid or a semi-fluid material • Cysts are common in the jaws than in any other bone many epithelial rests remaining in the tissues after dental development. A cyst is an epithelial lined pathologic cavity occurring in either hard or a soft tissue and may contain a fluid or a semi-fluid material Pseudocysts are cysts with no epithelial-linining. Pseudocysts True cyst Classification of Cysts Non odontogenic Odontogenic Inflammatory Developmental Odontogenic cysts radicular cyst dentigerous cyst OKC lateral periodontal gingival cyst Gorlin cyst orthokeratinized Inflammatory Odontogenic cysts Radicular or apical cyst with subclassification collateral cysts Paradental cyst Buccal bifurcation cyst Odontogenic cysts Arise from epithelial remnants (odontogenic epithelium) associated with the development of teeth & affect the toothbearing region of the jaws Inflammatory periodontal cyst Apical (periapical, radicular) Most common type of odontogenic cysts (55% of all cysts). Results from inflammatory hyperplasia of the epithelial rests of Malassez in the periodontal ligament following death of the pulp. Clinical Features:  Site: Maxilla especially the anterior region.  Related tooth : NON-VITAL 1. Asymptomatic discovered during routine radiographic examination 2. Swelling:  Hard  Later, eggshell crackling.  Then soft fluctuant swelling as the overlying bone is resorbed Radiographic appearance  Round well-defined radiolucency.  Narrow opaque margin (may not be apparent)  Related dead often has a large carious cavity or a filling.  Root resorption of the offending tooth or adjacent teeth may be noted Mechanism of Enlargement Epithelial mass increase in size proliferation Central portion separated from nutrition Central cells degenerate, become necrotic & liquify Form epithelial lined cavity filled with fluid Osmotic pressure is the pressure that must be applied to a solution to prevent the inward flow of water across a semi permeable membrane. Gross picture Cystic cut section Epithelial lining Histopathology Connective tissue wall Cyst lumen Histopathologic features C.T. wall Epithelial lining Cystic cavity Cholesterol clefts The epithelial lining is hyperplasia with elongated retepegs The epithelial lining is regular Rushton Bodies Hyaline bodies or Rushton bodies may be found within the epithelial lining. (Thin, linear, curved bodies. Brittle in nature Cholesterol crystals On aspiration from the cyst cholesterol crystals were observed in the obtained fluid Cholesterol clefts Foam cells Chronic inflammatory cells lymphocytes Plasma cells Multinucleated giant cells Newly & fully formed walls Non Keratinized proliferation Epithelial lining Hyaline or Rushton bodies histopathology Connective tissue wall Cholesterol clefts Inflammatory cells Multi nucleated Foreign body giant cells Foam cells Cyst lumen Cystic fluid (esinophilic) Cholesterol clefts Inflammatory Lateral Periodontal Cysts • Less common than periapical ones. • Related to the opening of a lateral root canal of a non vital tooth Residual Cyst  Radicular cyst persisted after extraction of the related tooth.  Residual cysts may cause trouble by interfering with the fitness of dentures, and sometimes enlarge to the extent of weakening the jaw with possible risk of jaw fracture Inflammatory collateral cysts Arise on the buccal aspect of roots of partially erupted or recently erupted teeth as a result of inflammation of pericoronal tissue Paradental cyst (60%) Buccal bifurcation cyst Arise on lower 3rd molar Arise on lower 1st or 2nd molar Cyst formation may be exacerbated Cyst formation may be exacerbated by buccal enamel extensions into the by food impaction bifurcation area Pain, swelling and trismus Painless swelling unless infected [tooth is usually tilted buccaly, with a deep periodontal pocket on the buccal aspect of the tooth ] Enucleation with extraction of involved 3rd molar Enucleation without extraction of the involved tooth Inflammatory collateral cysts Arise on the buccal aspect of roots of partially erupted or recently erupted teeth as a result of inflammation of pericoronal tissue Paradental cyst Buccal bifurcation cyst (60% of collateral cysts) well circumscribed unilocular radiolucency involving the buccal bifurcation and root area of the involved tooth . Buccal bifurcation cyst An occlusal radiograph is most helpful [as the root apices of the molar are tipped toward the lingual aspect]. Classification of Cysts Non odontogenic Odontogenic Inflammatory Developmental •Lateral periodontal cyst •Gingival cyst of adult •Gingival cyst of newborn •Odontogenic keratocyst •Dentigerous cyst •Calcifying odontogenic cyst •Glandular odontogenic cyst Developmental Odontogenic Cysts Dentigerous Cyst • It is a common developmental odontogenic cyst (20%) which is attached to the cervical region of an impacted tooth and envelopes its crown. • It arises due to fluid accumulation between the reduced enamel epithelium and the tooth crown, resulting in a cyst Dentigerous Cyst Clinical features: Highest incidence in 2nd & 4th decades. Associated with impacted tooth Maxillary & mandibular 3rd molars (75%) and maxillary canine areas Asymptomatic slow swelling expansion of bone unless infected Multiple dentigerous cysts are seen with cleidocranial dysplasia and Gardener’s syndrome Dentigerous Cyst Radiographic features: Well defined, unilocular radiolucent in association with the crown of an unerupted tooth surrounded by a radiopaque margin Macroscopic features: The cyst is attached to the cervical region of the tooth at cementoenamel junction Histopathologic Features • Cystic cavity lined by thin non keratinized layer of odontogenic epithelium • Mucous cells may also be present (metaplastic change). Thin regular stratified squamous epithelium attached to the tooth at the cementoenamel junction Mucous cells could be seen Treatment Enucleation of the cyst with removal of the unerupted tooth Complications 1. Jaw fracture 2. Give rise to ameloblastoma 3. Malignant transformation into mucoepidermoid or squamous cell carcinoma Eruption cyst  The eruption cyst is the soft tissue counterpart of the dentigerous cyst.  The eruption cyst appears as a soft swelling in the gingival mucosa overlying the crown of an erupting deciduous or permanent tooth. Eruption cyst Surface trauma may result in considerable amount of blood in the cystic fluid which imparts a blue to purple colour and referred to as eruption hematoma Eruption cyst Treatment  The cyst usually ruptures spontaneously, permitting the tooth to erupt.  If this does not occur , then simple excision of the roof of the cyst permits speedy eruption of the tooth. Non-inflammatory developmental cyst occurring adjacent or lateral to the root of a vital tooth due to proliferation of rests of dental lamina or reduced enamel epithelium or epithelial rests of Malassez Clinical features: • Site: mandible> maxilla, usually anterior to molars • Mostly asymptomsatic may exhibit small painless swelling • The related tooth is vital. Radiographic features: Lateral periodontal cyst appears as a small unilocular, teardrop-shaped radiolucent area. • not more than 1cm in diameter. • is surrounded by a thin sclerotic margin. Histopathologic Features • • Thin non keratinized stratified squamous epithelium, Clusters of clear cells are seen Cystic cavity The botryoid odontogenic cyst Is a polycystic variant of lateral periodontal cyst, resembling a cluster of grapes. Has a greater potential to recur Developmental Gingival Cyst of Adults: • Uncommon cyst of gingival soft tissue, occurring in alveolar mucosa • It arises from dental lamina rests. It represents the extraosseus counterpart of the lateral periodontal cyst Clinical Features: •It occurs at any age •Small (less than 1cm) well Circumscribed painless swelling of the gingiva •Same color as adjacent normal mucosa Developmental Gingival Cyst of Adults Radiographic features: • It’s soft tissue lesion so negative in x-ray Histopathologic Features • A pathologic cavity lined by stratified squamous epithelium • Clear cells may also be present. Treatment Local surgical excision Gingival Cyst of the New Born (Bohn’s nodules)  These are multiple white nodules seen on the alveolar ridge of a new born infant  Arising from remnants of the dental lamina Gingival Cyst of the New Born (Bohn ‘s Nodules): Histopathology: • Small keratin filled cystic cavity lined by thin epithelial lining Treatment  No treatment is required because these cysts rupture spontaneously Key points Odontogenic Cysts Ginigival cyst Eruption cyst Latral periodontal cyst Dentigerous cyst Buccal bifurcation cyst Residual cyst Periapical cyst Aims: The aim of this lecture is to detail the radiological and histopathological features of common odontogenic cystic lesions of the jaws. Objectives:  On completion of this lecture, the student should be able to:  Understand the radiological and histopathological features of common odontogenic cystic lesions of the jaws  Have an appreciation that radicular cysts are the most common of all cystic lesions of the jaws Reading material: Students are advised to review any relevant teaching provided in the first year. In addition they are advised to read relevant sections of the following texts: • Robinson M et al. Soames’ and Southam’s Oral Pathology. 5th edition. Oxford University Press, 2018 pp 136-147 • Odell E.W. Cawson’s Essentials of Oral Pathology and Oral Medicine. 9th Edition. Elsevier, 2017 pp 140-155 • Sheer M. Speight PM. Cysts of the Oral and Maxillofacial Regions. 4th Edition. Blackwell Munksgarrd 2007 pp1-228 (reference only) Thank you