Oral Pathology/ Radiology Flashcards
Which odontogenic epithelial cysts have their epithelial lining derived from:
- Rests of Malassez?
- Reduced Enamel Epithelium
- Remnants of Dental Lamina?
What is the site for 1 & 2?
- Radicular & Residual cysts (Inflammatory)
- Dentigerous & Eruptions cysts
- All other developmental cysts (OK, LPC, GCoA & GOC)
Rests of Malassez derived from proliferation of Remnants of Hertwig’s Root Sheath.
Site = Throughout PDL & trapped within the periapical granuloma
REE Site = On top of enamel (cyst formation due to split between REE & underlying enamel - usually at CEJ where tightest)
What are the 3 main pathogenesis stages/ requirements for cyst formation & growth?
- Source of Epithelium
- Stimulus for epithelial cell proliferation & cavitation
- Mechanism(s) for continued cyst growth & accompanying bone resorption
What is the main stimulus for epithelial cell proliferation in cyst formation?
What is an alternative mechanism?
Inflammation
Inflammatory cells secrete cytokines (IL-1, IL-6, TNF & GF) inducing Epidermal GF & Transforming GF Beta
Alternatively, possibly Genetic defects in tumour suppressor gene (e.g. Gorlin Goltz Syndrome)
What are the 3 mechanisms for continued cyst growth?
- Internal Hydraulic Pressure
- Bone Resorption
- Epithelial Proliferation (particularly important in Odontogenic Keratocyst)
What are 5 clinical features of cysts?
- Swelling
- Pain
- Displacement or loosening of teeth
- Egg-shell crackling (breaking of periosteal bone overlying cyst)
- Fluctuance (if cyst lies within soft tissue or perforates overlying bone)
What 5 things do you want to assess for on a cyst?
- Location
- Size & Locularity
- Shape
- Margin
- Effect on adjacent structures
What are the main indications for:
- Aspiration
- Excisional Biopsy
- Internal Biopsy
- Looking for blood, infection (e.g. pus) or keratin (by smear onto cytology slide or soluble protein estimation)
- Small lesion amenable for excision
- Large extensive lesion or reason to believe not a simple cyst
When completing aspiration for an odontogenic keratocyst - Is the soluble protein estimation high or low?
LOW soluble protein (less than 4g/100ml)
Cyst margins are often well defined & well-corticated, what are 2 exceptions to this?
- Solitary bone cyst (NON-corticated)
- Infections (loss of well defined margins)
Most cysts grow through hydrostatic mechanism (interna hydraulic pressure), what are 2 exceptions to this?
- Odontogenic Keratocyst - primarily via Epithelial proliferation
- Solitary Bone Cyst - Bone resorption
Explain the 3 cyst growth mechanisms…
1) Internal Hydraulic Pressure
- Protein in cyst wall acts as semi-membrane
- Fluid accumulation in cyst lumen → Positive pressure in cyst → Bone resorption from outwards pressure
2) Bone Resorption
Cyst secretion of pro-infammatory cytokines, TNF & PGE2 (fibroblasts) → Bone resorption
3) Epithelial Proliferation
Growth factors (e.g. EGF & TGFß) → Pronounced cyst epithelium proliferation
What are 3 key histological features in soft tissue cysts?
- Epithelial lining
- Mucin (positive purple stain)
- Lymphoid stroma
What are 6 cysts of soft tissues in the mouth, face and neck?
- Mucous Extravasation Cyst (minor SG)
- Mucous Retention Cyst (SG cyst)
- Ranula (SG cyst)
- Lymphoepithelial (Branchial) Cyst
- Dermoid & Epidermoid Cyst
- Thyroglossal Cyst
Which cyst might you suspect in a:
- Vital tooth?
- Non-vital tooth?
- Vital = Lateral Periodontal Cyst
- Non-Vital = Residual Cyst
What cyst histologies would you expect to see the following in?
- Cholesterol Clefts
- Mucous Metaplasia
- Hyaline Bodies
- Flat basement membrane
- Radicular cysts & Dentigerous (in lumen)
- Dentigerous cysts
- Odontogenic cysts (Radicular most often)
- ALL Developmental Odontogenic Cysts!
In histology of a Radicular cyst, what 5 things does the lumen contain?
- Pale pink serous exudate
- Cholesterol clefts
- Inflammatory cells
- Macrophages
- Desquamated epithelial cells
Name 4 inflammatory bone disorders (that u need to know for path)…
- Dry Socket (Localised Alveolar Osteitis)
- Osteomyelitis
- Osteoradionecrosis
- Medication-related Osteonecrosis (MRONJ)
Name 4 fibro-osseous bone disorders (that you need to know for oral path)…
Which one is neoplastic?
- Fibrous Dysplasia
- Ossifying/Cemento-Ossifying Fibroma (COF) - NEOPLASTIC
- Cemento-Osseous Dysplasia
- Paget’s disease
What is the definition of a:
- Premalignant Lesion? (Give 2 examples)
- Premalignant Condition?
-
Premalignant Lesion = Morphologically altered tissue where cancer is more likely to occur than in “normal” tissue counterpart
E.g. Leukoplakia (Homogenous/Non-Homogenous) or Erythroplakia - Premalignant Condition = Generalised state associated with significantly increased malignancy risk
What are 5 Premalignant Conditions?
- Lichen Planus (~0.2-5%)
- Syphilis
- Submucus Fibrosis
- Patterson-Kelly / Plummer-Vinson Syndrome (Sideropenic Dysphagia)
- Actinic Keratosis
What is seen histologically in Leukoplakia? (6)
- Hyper- or Para-keratosis (→ white appearance)
- Variable hyperplasia and acanthosis (increased prickle cell layer thickness)
- Atrophy
- Inflammation
- +/- Candidal Hyphae (30%)
- +/- Dysplasia
What 3 things occur in acanthosis?
- Increased number of cells → Thickening in prickle cell layer
- Broadening of rete ridges
- Thicker epithelium