Radiolucencies Part 1 Flashcards
List the Bone/Radiographic Description
-New (Number)
-Students (Size)
-See (Shape)
-Part (Periphery)
-Description (Density)
-Loving (Location)
-Education (Effect)
Periapical Granuloma/Cyst
-Inflammation in the pulp leading to involvement of the periapical tissues
-Most common odontogenic cyst
-Acute cases are painful; chronic cases are asymptomatic
-Acute exacerbation of a chronic lesion can cause an abscess with or without swelling
How does a Periapical Cyst/Granuloma appear radiographically?
-Round to ovoid radiolucency at the apex of a non-vital tooth
-Typically cause loss of lamina dura and can cause root resorption
-Most are <1.5cm in diameter
-Can’t distinguish by size or radiographic appearance (granuloma vs. cyst)
-Less commonly between teeth (lateral radicular cyst)
Describe the histology of a Periapical Cyst/Granuloma
-Acute/chronic inflammation and granulation tissue (capillaries and immature fibroblasts)
1. WITH a variably thick, non-keratinized stratified squamous epithelial lining –> periapical cyst
2. W/O an epithelial lining –> periapical granuloma
**Note: NO granulomatous inflammation
Describe the tx for a periapical cyst/granuloma
-Enucleation, with either extraction or endodontic therapy of the involved tooth
-If the lesion is not removed, a residual periapical cyst may result
-Recurrence is unlikely
PA cyst/granuloma - when to worry?
- Multilocular- not odontogenic infection
- Significant root resorption or movement of teeth- increases chances that could be something else (perform tooth vitality test - if vital, start thinking it may be something else)
- Does not respond to tx radiographically or clinically- think either inadequate tx or different diagnosis
Parulis
-Yellowish/red nodule of granulation tissue representing an intraoral point of drainage for a sinus tract related to necrotic tooth
-Typically facial gingiva/alveolar mucosa apical or near tooth of origin (exceptions: palatal bone, mx lateral incisors, lingual plate, md 2nd and 3rd molars)
-Asymptomatic lesions are often patent and pus can be expressed from the center of the lesion
List the Developmental Cysts
-Dentigerous cyst/Hyperplastic dental follicle
-Eruption cyst
-Lateral periodontal cyst
-Odontogenic keratocyst
-Nasopalatine duct cyst
-Simple bone cyst (not a true cyst but mimics)
Describe the background of cysts
-Cyst: Abnormal sac or cavity lined by epithelium which is enclosed in CT
-Enlargement comes from fluid accumulation inside
-Developmental (may be inside bone (intraosseous) or soft tissue (extraosseous))
1. odontogenic
2. nonodontogenic (happens at planes of fusion)
-Inflammatory (periapical cyst, residual cyst)
Where do odontogenic cysts/tumors come from?
-Dental lamina rests (rests of Serres): due to initial invagination of tooth formation
-Rests of Malassez: due to root development
-Reduced enamel epithelium: due to crown development
**All due to epithelial/CT fragments
Dentigerous Cyst
-By definition, a cyst that forms around the crown of an impacted tooth (pericoronal)
-Second most common odontogenic cyst
-This is a developmental (as opposed to inflammatory) cyst
-Arises from reduced enamel epithelium; shows a thin, non-keratinized stratified squamous epithelium
- >3-4mm pericoronal radiolucency, smaller lesions are virtually identical to a hyperplasstic dental follicle (lack a true epithelial lining)
-Tx: enucleation of squamous lining and fibrous wall
-Prognosis is excellent - minimal tendency to recur
-Tissues should be submitted for microscopic examination to exclude other possible diagnoses
When is it NOT a dentigerous cyst?
-Not around the crown
-Multilocular
-Any sign or opacity: this changes the differential completely!
When is it less likely to be a dentigerous cyst?
-Impacted tooth other than 3rd molar or canine
-Larger lesions
Dentigerous Cyst Diff Dx (mimics)
-Odontogenic keratocyst- most common
-Unicystic ameloblastoma- infrequent
-Odontogenic myxoma- uncommon
-Central giant cell granuloma- anterior of the first molar (don’t expect in the posterior mandible/ramus)
Eruption Cyst
-Essentially represents a dentigerous cyst that forms in the soft tissue overlying the crown of an erupting tooth
-Usually somewhat translucent swelling but may be bluish b/c of blood accumulation
-Children generally affected
-Take a radiograph to confirm
-Tx: usually ruptures spontaneously or can excise the roof to allow the tooth to erupt
Lateral Periodontal Cyst
-Derived from dental lamina rests
-Middle aged adults
-Asymptomatic - adjacent teeth are vital
-Usually unilocular radiolucency; can look multilocular (grape-like - called botryoid odontogenic cyst)
-Canine/premolar region, moat often mandibular
- <1cm
-Excision is curative
Gingival Cyst of the Adult
-Identical to the lateral periodontal cyst but occurs with gingival soft tissues, not within bone
-Bluish to translucent/clear swelling, often centered in attached gingiva (can mimic a mucocele but there are no salivary glands on the gingiva)
-Excision is curative
-Parulis can also mimic this (but a parulis will most liekly be associated with a non-vital tooth)
Nasopalatine Duct Cyst
-Also known as incisive canal cyst
-Located within the incisive canal (in bone) which often causes a palatal swelling over the foramen
-Radiolucency between apices of #8-9 in middle-aged adult
-Vital teeth
-Tx: surgical removal. Rare recurrence
Odontogenic Keratocyst
-Benign but locally aggressive developmental odontogenic cyst
-Probably arises from dental lamina rests
-Affects a wide range
-Most commonly seen in the posterior mandible, but any segment of the jaws can be affected - clinically may mimic a wide variety of jaw cysts
-Often asymptomatic or causes swelling when large
-Unilocular radiolucency when small. Multilocular appearance often develops as the lesion enlarges
Odontogenic Keratocyst Histology
-Uniform, thin stratified squamous epithelial lining
-Luminal parakeratin production
-Palisaded (“picket fence”) appearance of the basal cell nuclei
-Features altered with inflammation
-Satellite cyst formation may be seen
Odontogenic Keratocyst Tx and Recurrence
-Some controversy as to best tx:
1. Small lesions: excision with curettage
2. Large lesions: resection, marsupialization followed by surgical excision of residual cystic epithelium
- 33% recurrence rate overall; larger lesions are more likely to recur
-With occurrence in the first decade, or with multiple OKC’s, nevoid basal cell carcinoma syndrome (Gorlin syndrome) should be ruled out
Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome)
-Autosomal dominant condition
-OKCs of the jaws are a characteristic finding in these patients
-These often arise at an early age and may be multiple
-Cutaneous features:
1. basal cell carcinomas, early onset
2. palmar/plantar pitting
-Skeletal features:
1. calcified falx cerebri
2. increased cranial circumference
3. bifid ribs
-Tx/Management: sun screens; excision of basal cell carcinomas as needed; monitor for and excise OKCs; genetic counseling
Simple Bone Cyst
-Also known as “traumatic bone cyst” though trauma isn’t present in most cases - theory
-Young patients (age 10-20)
-In jaws, mandible only - molar/premolar region
-Painless, expansion/swelling in up to 25% of cases
-Teeth are vital!
Simple Bone Cyst - radiographs, diagnosis, tx
-Radiographs: Well-defined radiolucency that “scallops” between adjacent roots
-Diagnosis: Biopsy - no cyst lining, just a hole in the bone
-Tx: Scrape (curettage) inside of bony cavity to promote bleeding and regeneration of bone
-Follow-up radiographs to confirm bone fill
