Quartz 4

5. Odontogenic and Non-Odontogenic Cysts

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Oral Pathology module: Odontogenic and non-odontogenic cysts

Definition

A cyst is a pathological cavity filled with fluid, semi-fluid or gaseous contents and is not created by an accumulation of pus.

Aetiology and pathogenesis

Clinical features

  • Noticeable swelling
  • Discharge into the mouth
  • Pain due to secondary infection

Diagnosis

  • Combination of adequate history, clinical examination and selected investigation (radiographs)

CLASSIFICATION: Cysts of the Jaws

Inflammatory Odontogenic Cysts

RADICULAR CYSTS

Clinical Features

  • 60-75% of all jaw cysts (Most Common)
  • Peak in 4th and 5th decades
  • Non-vital tooth
  • Upper lateral incisor - most common tooth
  • Rare in deciduous teeth
  • Asymptomatic or expansion → springy → egg-shell crackling → fluctuation
  • Infection → pain
  • Radicular Cyst can be:
    • Apical
    • Lateral
    • Residual Radicular Cyst

L5 cysts, p.12

**Radiographic Features

  • Shape: Monolocular
  • Outline: Well defined, Well corticated
  • Radiodensity: Uniformly radiolucent
  • Vitality : teeth usually become non-vital

Pathogenesis

  • **INITIATION
    • Cell rest of Malassez activated
    • Activated by products of necrotic pulp
  • CYST FORMATION
    • Degeneration and death of central cells leads to cavitation
  • CYST ENLARGEMENT
    • increased osmolality due to breakdown products becoming smaller and more osmotically active
    • wall acts as semi-permeable membrane

L5 cysts, p.20

Cysts Contents

  • Breakdown products of cells
  • Serum proteins
  • Water and electrolytes
  • Cholesterol crystals

**Histopathology

  • Periapical granuloma with epithelial proliferation - polymorphs in epithelium Granulation tissue = endothelial cells from new blood vessels and a little amount of collagen fibers from fibroblasts

  • Cyst lined by irregular, non-keratinised stratified squamous epithelium

  • Foam cells, lymphocytes, plasma cells, cholesterol clefts, surrounding fibrosis

    • Foam cells = macrophages
      • They are called foam cells because the macrophages become enlarged and have cloudy cytoplasm

  • Lining becomes thinner and less inflamed

  • 10% contain hyaline (Rushton) bodies

  • Cholesterol dissolves in alcohol, during preparation of the ssmaple it will dissolve, leaving the clefts

  • Image shows “Hematosomes”:

  • Rushton bodies:

**PARADENTAL CYST

  • Partially erupted lower 3rd molar usually with pericoronitis
  • Buccal/Disto-buccal aspect
  • Enamel spur from bucco-cervical margin of root furcation
  • Histologically resembles radicular cyst
  • Derived from reduced enamel epithelium
  • Paradental cysts are usually attached to the Neck of the tooth

Developmental Odontogenic Cysts

DENTIGEROUS CYST

  • Cyst enclosing crown of an unerupted tooth
  • Attached to cemento-enamel junction
  • Follicular cyst is another name
    • Often used because its related to the dental follicle
  • We can never see a dentigerous cyst in an unerupted tooth

PATHOGENESIS

  • Intrafollicular fluid accumulates between Reduced enamel epithelium and enamel
  • Pressure of tooth on impacted follicle causes
    • Obstruction of venous outflow
    • Serum transudation
    • Exudation

Radiographs

CLINICAL FEATURES

  • 10-15% of cyst
  • Children and young adults
  • Permanent teeth
  • Upper canine and lower 3rd molar — teeth likely to be impacted
  • M:F 1.6:1
    • Males are more affected
  • Painless enlargement — missing tooth
  • Tilting of tooth
  • Root resorption
  • Radicular cysts usually happen in middle age, but dentigerous cysts happen at younger ages

PATHOLOGY

  • Clear yellow fluid — cholesterol
  • Purulent if infected
  • Lined by flattened, non-keratinised stratified squamous epithelium
  • Continuous with reduced enamel epithelium
  • Mucous and ciliated columnar metaplasia
  • Fibrous wall with variable inflammation

ERUPTION CYST

  • Extra-alveolar dentigerous cyst
  • Deciduous tooth or permanent molar
  • Fluctuant bluish swelling
  • Haemorrhage into cyst common
  • Most spontaneously resolve
    • Better to make an incision that allows the tooth to erupt to help it laong

Relative Frequency of Cysts

Odontogenic (90%)Non-odontogenic (10%)
Radicular 60-75%Nasopalatine 5-10%
Dentigerous 10-15%Others 1%
Keratocyst 5-10%
Paradental 3-5%
Gingival 1%
Lateral periodontal 1%
  • There are some genetic disruptions that occur specifically keratocytes
    • Sometimes they have a high recurrence and can come back in an aggressive form

ODONTOGENIC KERATOCYST

CLINICAL

  • 5-10% of all jaw cysts
  • SITE
    • 70-80% mandible
      • Most frequent in the posterior mandible
    • 50% angle/ramus
  • Often asymptomatic
  • M>F
  • Swelling, discharge, pain, pathological fracture, tooth displacement, rarely buccal expansion
    • Can cause fracture of the mandible when it becomes very large
  • 10% of cases of keratocysts have multiple cysts
  • High recurrence rate

PATHOGENESIS

  • Derived from the dental lamina or it’s remnants - cell rests of Serres
  • Originate from enamel organ (tooth primordium) of a tooth before hard tissues develop:
    • normal tooth
    • supernumerary

RADIOLOGICAL APPEARANCE

  • Well demarcated radiolucency
  • Pseudolocular or multilocular, often with scalloped periphery
  • Root or tooth displacement

[[L5 cysts.pdf#page=44&selection=0,0,0,14&color=yellow|HISTOPATHOLOGY]]

  • Regular stratified squamous epithelium
  • Thin epithelial layer (5-8 cells thick)
  • Palisaded basal layer
    • The basal cells have a hypertraumatic blue nuclues
    • Slightly columnar appearance
    • Aligned in a consistent way
    • Palisaded Basal Cells = looks like a fence
  • Corrugated surface which can be parakeratinised or orthokeratininsed
  • Thin, friable fibrous capsule - little inflammation
  • Satellite (daughter) cysts
    • The daughter cysts in the cyst wall is what causes the recurrence rates !

Enlargement

  • Cancellous enlargement antero-posteriorly
  • Little or no bucco-lingual expansion → large, especially in angle and ramus of mandible

RECURRENCE

  • Up to 60%
  • Size and infiltrative nature
  • Tendency to multiplicity and satellite cysts
  • Intrinsic growth potential
  • Thin, friable capsule
  • Genetic - multiple basal cell naevus syndrome (Gorlin-Goltz)

GORLIN - GOLTZ SYNDROME

  • Multiple keratocystsis the main defining feature of Gorlin-Goltz syndrome
  • Multiple basal cell naevi which can develop into basal cell carcinomas
  • Patient may also have Skeletal abnormalities
    • bifid ribs
    • spine defects
  • Frontal bossing and hypertelorism
  • Calcification of the falx cerebri

LATERAL PERIODONTAL CYST

L5 cysts, p.49

CLINICAL FEATURES

  • Canine/premolar area
  • Rare < 20 years
  • Adjacent teeth vital
  • NB - Differential diagnosis

**RADIOGRAPHY

  • Well defined radiolucent area lateral to tooth

HISTOPATHOLOGY

  • Derived from reduced enamel epithelium or cell rests of Malassez
  • NKSSE 2-6 cells thick
  • Periodic thickening in luminal surface of epithelium

GINGIVAL CYSTS

INFANTS

  • Bohn’s nodules, Eptein’s pearls
  • Common in newborns and up to 3 months
  • Usually rupture or spontaneously involute
  • 2-3 mm keratinising stratified squamous epithelium
  • Arise from the cell rests of Serres

ADULT

  • Slow -growing, usually < 1cm diameter
  • Cause a large swelling
  • Free or attached gingiva or interdental papilla
  • Tooth vital
  • Pathogenesis
    • odontogenic
    • implantation

Non-Odontogenic Developmental Cysts

  • The non odontogenic cysts are called Nasoplatlaine duct cysts and nasolabial(naso-alveolar cysts)
    • The old classifications of median cysts and globulomaxillary cyst have been removed

NASO-PALATINE DUCT CYST

  • Incisive canal cyst
  • Remnants of nasopalatine duct
  • M:F 4:1
  • 30-60 years
  • Swelling of midline of anterior hard palata
  • Pain and discharge
  • Mucoid and salty
  • Anterior Teeth are vital
    • No source of infection

RADIOLOGY

  • Well defined radiolucency between roots of central incisors
  • Roots may diverge
  • Intact lamina dura

L5 cysts, p.57

**HISTOPATHOLOGY

  • Respiratory type epithelium
  • Stratified squamous epithelium
  • Blood vessels and nerves in wall Histological image of pseudostratified columnar epithelium with cilia.

NASOLABIAL CYST

  • Swelling in nasolabial fold below alae and leading to loss of fold
  • Sometimes bilateral
  • Swelling, pain, difficulty in nasal breathing
  • Nasolabial cysts are soft tissue lesions

PATHOGENESIS

  • epithelium enclosed at a site of ‘fusion’ of globular, lateral nasal and maxillary processes — unlikely
  • remnants of embryonic nasolacrimal rod or duct

HISTOPATHOLOGY

  • Non-ciliated columnar, respiratory type or stratified squamous epithelium

Non-Epithelial (Primary Bone) Cysts

SOLITARY BONE CYST

  • Also called simple, haemorrhagic, traumatic bone cysts
  • Rare
  • Mandible, usually in second decade
  • Radiolucent area extending between roots (scalloping), usually without expansion
  • Resolves with minimal intervention

L5 cysts, p.60

**HISTOPATHOLOGY

  • No epithelium
  • Vascular fibrous tissue in the cyst wall Radiographic and histological images of a Solitary Bone Cyst.

ANEURYSMAL BONE CYST

  • Radiolucent area bulging into adjacent soft tissue
  • Mostly in children and young adults
  • Blood filled spaces - non endothelial lined
  • Giant cells, haemorrhage, osteoid
  • Giant cell lesion
  • Very aggressive type of cysts Cyst wall Sometimes the cyst linig isn’t consistent, some areas are thick while othes are then Cyst lining Needs are: cholesterol clefts

Graph View

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