BDS10011 Cystic Lesions of Bone (2) PDF

BDS10011 Cystic Lesions of Bone (2) Aims: The aim of this lecture is todetail the radiological and histopathological features of uncommon cystic lesions of the jaws and allied structures. Objectives: On completion of this lecture, the student should be able to: Understand the radiology and histopa...

BDS10011 Cystic Lesions of Bone (2) Aims: The aim of this lecture is todetail the radiological and histopathological features of uncommon cystic lesions of the jaws and allied structures. Objectives: On completion of this lecture, the student should be able to: Understand the radiology and histopathology of the spectrum of cystic lesions that can arise in the jaws and allied structures 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 Odontogenic cysts radicular cyst dentigerous cyst OKC lateral periodontal gingival cyst Gorlin cyst orthokeratinized Prevalence of odontogenic cysts according to data reported by WHO 2017  Developmental odontogenic cyst with aggressive clinical behavior & high recurrence rate Clinical Features: Mostly occurs in 2nd or 3rd decade of life Common in the ramus area of mandible Usually asymptomatic, but larger lesions may cause pain and swelling It grows in an anteroposterior direction without causing bone expansion large at first presentation Radiographic features: multilocular radiolucent area with typical soap bubble appearance and scalloping border Cheesy white aspirate Macroscopic appearance Cystic cavity shows corrugated appearance & contain keratin •lined by parakeratinized epithelial lining which is thin, folded (About 5-8 layers) regular, with no retepeg formation •loosely attached to underlying C.T. •the basal cells are tall columnar palisaded described as tombstone appearance Palisading of basal cells Budding & daughter cysts Treatment It depends on the extent of the cyst and the degree of multilocularity. It ranges from enucleation either preceded by marsupilization or not, as well as resection for larger lesions. Recurrence rate is about 25%, it is reduced to 8% [Carnoy’s solution] and 2% [resection] The high recurrence rate is due to: 1. Presence of budding and daughter cysts 2. Loose attachment between epithelium & C.T. Multiple odontogenic keratocysts may be associated with nevoid basal cell carcinoma (Gorlin-Goltz syndrome) syndrome May be associated 1-multiple keratocysts 2- bifid ribs 3- Basal cell carcinoma Multiple odontogenic keratocysts may be associated with nevoid basal cell carcinoma (Gorlin-Goltz syndrome) syndrome Orthokeratinizing odontogenic cyst  It is a cyst that is lined by orthokeratinized epithelium.  Although such lesions were originally called orthokeratinized variant of odontogenic keratocyst, it is generally accepted that they are different  No special clinical and radiographic features, it resembles other cysts. Treatment   Enucleation and curettage is the usual treatment. Recurrence is rare [unlike odontogenic keratocyst] Calcifying odontogenic cyst (Gorlin cyst) Uncommon cyst Has 3 variants: solid , cystic, neoplastic Clinical features     2nd decade about (30 years) Painless swelling Anterior part of maxilla Some lesions are associated with odontomas  Extraosseous lesions present as gingival swellings Calcifying odontogenic cyst (Gorlin cyst) Radiographic features  Unilocular or multilocular radiolucency, with multiple small radiopaque foci  one third of cases are associated with unerupted tooth, most often a canine. Calcifying odontogenic cyst (Gorlin cyst) Histopathologic features  Cystic cavity lined by keratinized epithelium with variable thickness [basal:ameloblast like cells and overlying stellate reticulum like cells]  Accumulation of Ghost cells are seen, may undergo calcification  Dentinoid [areas of an eosinophilic matrix material that represent dysplastic dentine] Glandular Odontogenic Cyst It is a rare developmental odontogenic cyst with epithelial features that simulate salivary gland or glandular differentiation that shows aggressive behavior. Clinical features:  It mostly occurs in middle age  Mostly occurs in anterior area of the mandible and crosses the midline  Small lesions (less than 1 cm) are usually asymptomatic  Large lesions can cause expansion of the bone, parasthesia and pain. Glandular Odontogenic Cyst Radiographic features: Unilocular or multilocular radiolucency with scalloped border Glandular Odontogenic Cyst Histopathologic features:  The glandular odontogenic cyst is lined by squamous epithelium of varying thickness. It exhibits a) Surface columnar cells with cilia. b) Small microcysts c) Clusters of mucous cells are present. Glandular Odontogenic Cyst Treatment:  Enucleation or curettage .  Because of its potentially aggressive nature and tendency for recurrence ,en bloc resection, particularly for multilocular lesions. Key points Odontogenic Cysts Ginigival cyst Eruption cyst Latral periodontal cyst Glandular odontogenic Residual cyst cyst Odontogenic keratocyst Dentigerous cyst Buccal bifurcation cyst Periapical cyst Other Cysts Non odontogenic 1. Nasopalatine duct cyst & cyst of palatine papilla 2. Nasolabial cyst Pseudocysts Soft tissue cyst NON-ODONTOGENIC CYSTS These are cysts in which the epithelial lining is derived from ectoderm involved in development of facial tissues Nasopalatine tract cysts Nasopalatine duct cyst Most common non-odontogenic cyst Cyst of palatine papilla Nasopalatine duct cyst Is a cystic lesion arising from proliferation & subsequent cystic degeneration of epithelial remnants of nasopalatine duct [embryonic structure connecting oral and nasal cavities] Clinical Features: •. Between 4th and 6th decades. • Asymptomatic, slowly growing swelling on the anterior of the hard palate •The adjacent incisors are vital Radiographic features • Small round or heart-shaped [due to superimposition of the nasal septum] radiolucent area , in the midline between the roots of the maxillary central incisors. • Displacement of maxillary central incisors roots is seen Radiographic features • Small round or heart-shaped [due to superimposition of the nasal septum] radiolucent area , in the midline between the roots of the maxillary central incisors. • Displacement of maxillary central incisors roots is seen Histopathologic Features Cystic cavity lined by stratified squamous epithelium or pseudostratified ciliated columnar epithelium The C.T. wall shows neurovascular bundles and mucous glands Cyst of incisive papilla When nasopalatine duct cyst occur in the soft tissue of the incisive papilla area without any bony involvement.  It appears as bluish swelling discharging a salty fluid x-ray is negative. Other Cysts Non odontogenic Pseudocysts 1. Static bone cyst 2. Traumatic bone cyst 3. Aneurysmal bone cyst Soft tissue cyst Traumatic bone cyst Air filled (empty) cavities that lack epithelial lining and locate predominantly in the posterior mandible Etiology: it may originate due to trauma that causes bleeding and haematoma formation within bone. Instead of clot organization, it breaks down leaving an empty cavity within the bone. Clinical Features: • adolescents & children •Asymptomatic [usually discovered accidentally] •Slowly growing Traumatic bone cyst Radiographic Features: • well defined unilocular radiolucency that scallop around the roots of teeth. •it does not displace teeth or resorb roots • it occurs above the inferior dental canal Histopathological Features: • Thin connective tissue lining or no lining at all Aneurysmal bone cyst A pseudocyst characterized by intrabony accumulation of blood filled spaces It may arise due to increased venous pressure which results in dilation and rupture of blood vessels followed by stimulation of resorption of the surrounding bone. It may arise due to vascular malformation that leads to development of a dilated vascular spaces. Aneurysmal bone cyst Clinically •It is seen in age below 30 in the mandibular posterior area. •It causes painful swelling of the bone. •At the time of operation there is excessive bleeding of dark venous blood. Radiographic Features: It is characterized by: Radiographically, radiolucency. multilocular Marked cortical expansion thinning[ballooning or blow out] & Aneurysmal bone cyst Histopathology •Large spaces filled with blood, surrounded by a fibrous connective tissue. •The connective tissue contains multinucleated giant cells and trabeculae of osteoid and bone spicules. •The spaces are not lined by endothelium. Other Cysts Non odontogenic Soft tissue cysts occur in the lip, floor of mouth, neck & salivary gland areas Pseudocysts Soft tissue cyst 1.Mucous extravasation & mucous retention cyst 2. Dermoid & epidermoid cyst 3.Branchial cleft (lymphoepithelial) cyst 4. Thyroglossal tract cyst Cysts of the salivary glands Mucous extravasation cyst Mucous retention cyst pseudocyst True cyst Due to trauma of excretory duct Due to obstruction of salivary leading to escape of mucin into flow because of salivary duct surrounding connective tissue stone Mucous extravasation cyst (mucocele) Clinical Mostly in minor salivary features glands (lip) in children & young adults Asymptomatic, soft, fluctuant swelling , appear bluish (superficial lesions) Mucous retention cyst In major (more common) or minor salivary glands mostly in adults Asymptomatic, soft, fluctuant swelling , appear bluish Mucous extravasation Mucous retention cyst cyst Histological Mucin pool surrounded by Cystic cavity contains mucin features a granulation tissue & lined by ductal infiltrated by chronic epithelium inflammatory cells Ranula A clinical term that describes mucous retention & extravasation cysts in the floor of mouth [related to sublingual gland] and appear as blue fluctuant swelling Dermoid and Epidermoid Cysts They are generally classified as a benign cystic form of teratoma [a developmental tumor composed of tissues from 3 germ layers] Clinical Features: • most common in children & young adults •Located in the midline of floor mouth •Usually slowly growing, painless, rubbery swelling Dermoid and Epidermoid Cysts Histopathological Features: A cyst lined by keratinized squamous epithelium. skin appendages (hair follicles & sebaceous glands) may be seen. When the cyst is lined by epidermis-like epithelium and contain thick keratin, it is often called epidermoid cyst Thyroglossal Tract Cyst Developmental lesion that arise from remnants of thyroglossal duct Thyroglossal Tract Cyst Clinical Features: •Located in the midline anywhere along the thyroglossal tract, from foramen caecum of the tongue to the caudal cervical area of the neck •Asymptomatic, fluctuant, movable swelling •Lesions at the base of tongue may cause laryngeal obstruction Thyroglossal Tract Cyst Histopathological Features: The cyst lining varies depending upon its location above the level of the hyoid bone stratified squamous epithelial lining if below the level of the hyoid it is respiratory epithelium. The connective tissue wall of the cyst contains thyroid follicles Complications: 1. Dysphagia and difficulty in eating and speech. 2. Malignant transformation of epithelial lining into papillary adenocarcinoma. Other Cysts Non odontogenic 1. Nasopalatine duct cyst & cyst of palatine papilla 2. Nasolabial cyst Pseudocysts 1. Static bone cyst 2. Traumatic bone cyst 3. Aneurysmal bone cyst Soft tissue cyst 1.Mucous extravasation & mucous retention cyst 2. Dermoid & epidermoid cyst 3.Branchial cleft (lymphoepithelial) cyst 4. Thyroglossal tract cyst Key points Aims: The aim of this lecture is to detail the radiological and histopathological features of uncommon cystic lesions of the jaws and allied structures. Objectives: On completion of this lecture, the student should be able to: Understand the radiology and histopathology of the spectrum of cystic lesions that can arise in the jaws and allied structures 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 136-159 • Odell E.W. Cawson’s Essentials of Oral Pathology and Oral Medicine. 9th Edition. Elsevier, 2017 pp 140-164 • Sheer M. Speight PM. Cysts of the Oral and Maxillofacial Regions. 4th Edition. Blackwell Munksgarrd 2007 pp1-228 (reference only) Thank you