1. Traumatic Bone Cys
1.1. 1. Info
1.1.1. 1. lacks epithelium lining not true
1.1.2. 2. bone cavity with few fluid content
1.2. 2. pathogenesis
1.2.1. 1. not clear although most believe due to trauma causing bleeding and haematoma
1.2.2. 2. when clot formed breaks down leaving empty cavity within bone
1.2.3. 3. expansion occurs until cortical bone is reached
1.2.4. 4. 80% history of trauma
1.3. 3. clinical
1.3.1. 1. below 40
1.3.2. 2. site: mandible body and ramus in molar premolar area
1.3.3. 3. more in long bones than in jaw
1.3.4. 4. most cases symptomless
1.3.5. 5. doesn't cause cortical expansion in most cases
1.3.6. 6. swelling seen in 25%
1.3.7. 7. teeth vital and not loosened
1.4. 4. radio
1.4.1. 1. cyst vary in size may extend to ramus
1.4.2. 2. above inferior alveolar canal
1.4.3. 3. unilocular cavity well defined
1.4.4. 4. cyst prject into interradicular septa
1.4.5. 5. produce scalloped contour
1.4.6. 6. anterior usually regular round or oval
1.4.7. 7. teeth may be displaced but rarely resorbed
1.4.8. 8. they don't become divtalized or mobile
1.4.9. 9. lamina dura is intact or partially lost
1.5. 5. histopathology
1.5.1. 1. may contain remnants of blood or blood stained fluid
1.5.2. 2. lining is thin fibrous or granulation tissue with no epithelial component
1.5.3. 3. red cells and hemosiderin may be seen in cavity
1.6. 6. treatment
1.6.1. 1. opened surgically and irrigated with saline then walls scratched to cause bleeding
1.6.2. 2. then bone repair occurs
2. Aneurysmal Bone Cyst
2.1. 1. etiology
2.1.1. 1. increased venous pressure
2.1.2. 2. dilated vascular bed in bone area
2.1.3. 3. resorption of bone by giant cells then occur and replaced by ct, osteoid and new bone
2.1.4. 4. less commonly may arise in central haemangioma
2.2. 2. clinically
2.2.1. 1. age: under 30 years of age
2.2.2. 2. sex slightly more in female
2.2.3. 3. site long bones and jaws molar area
2.2.4. 4. appearance
2.2.4.1. 1. firm swelling, lesion is painful and tender
2.2.4.2. 2. upon entering lesion excessive bleeding is encountered resembling blood soaked sponge
2.3. 3. radio
2.3.1. 1. multilocular with honeycomb or soap bubble appearance due to septa of new bone
2.4. 4. histopathologic
2.4.1. 1. fibrous ct containing blood filled spaces
2.4.2. 2. spaces not lined by endothelium
2.4.3. 3. cystic cavity lined by fibroblast histiocytes, extravasated rbc and hemosiderin and multinucleated giant cell
2.4.4. 4. new osteoid tissue formed in various amounts
2.5. 5. treatment
2.5.1. 1. curettage or excision
3. Static bone cyst (Developmental Mandibular Salivary Gland Depression)
3.1. 1. Etiology
3.1.1. 1. caused by developmental inclusion of submandibular salivary tissue in lingual surface of mandible may be uni/bilateral
3.2. 2. Clinical
3.2.1. 1. asymptomatic
3.2.2. 2. treatment not required
3.3. 3. radio
3.3.1. 1. round to ovoid sharp circumscribed radiolucency with or without RO margin
3.3.2. 2. below inf alv canal
3.3.3. 3. constant size and shape (static)
3.3.4. 4. confirmed by Sialogram (RO) material injected to duct of submandibular gland of affected side, presence of slivary tissue in cyst can be detected