1. Pseudotumors and Cysts
Assoc. Professor Jan Laco, MD, PhD

2. Causes of swellings of jaws
Cysts
odontogenic x non-odontogenic
Odontogenic tumors
Giant cell lesions
Fibro-osseous lesions
Non-odontogenic tumors of bone
Metastatic tumors
Chronic osteomyelitis

3. Cysts of jaws = pathological cavity lined by epithelium
RTG: sharply-defined lucencies
± fluid
slowly growth  teeth displacement
asymptomatic x infection  painfull
rarely: pathological fracture
compressible and fluctuant swelling if extending into soft tissues
appear bluish when close to mucosal surface

4. Cysts of jaws Odontogenic developmental inflammatory dentigerous
eruption
gingival
lateral periodontal
odontogenic keratocyst
calcifying odontogenic cyst
inflammatory
radicular / residual
inflammatory collateral (paradental)

5. Cysts of jaws Non-odontogenic Pseudocysts nasopalatine duct nasolabial
surgical ciliated cyst
Pseudocysts
solitary bone “cyst“
aneurysmal bone “cyst“
Stafne´s “cyst“

6. Cysts of jaws – frequency (%)
1. radicular
2. dentigerous
3. keratocyst
4. nasopalatine

7. Radicular cyst most common swelling of jaws / cyst
 males (M : F … 3 : 2)
years
maxilla : mandible … 3 : 1
painless swelling
enucleation

8. Radicular cyst at tip of root of tooth with necrotic pulp (caries)
pulpitis  periodontitis  periapical granuloma  proliferation of Malassez nests  central liquefaction
Mi: hyperplastic non-keratinizing squamous epithelium (net-like) ± hyaline (Rushton) bodies
wall: granulation tissue + fibrous tissue
mixed inflammation
hemosiderin, cholesterol clefts ± granulomas

9. Odontogenic cysts residual cyst lateral radicular cyst
radicular cyst left behind after tooth extraction
spontaneous regress
lateral radicular cyst
at side of nonvital tooth
lateral branch of root canal
enucleation

10. Inflammatory collateral cyst
inflammation around partially erupted tooth
paradental cyst: lower M3
mandibular buccal bifurcation cyst: lower M1 and M2
 males, children or adults aged years
vital tooth with pericoronitis
Mi: ~ radicular cyst
enucleation

11. Dentigerous (follicular) cyst
cystic change of enamel organ after complete enamel formation
fluid accumulation between crown and collapsed enamel organ
surrounds crown + attached to tooth neck at amelo-cemental junction  crown inside (RTG)
M : F … 2 : 1
years
mandibular M3, maxillary C  prevents eruption
Mi: thin squamous epithelium (2-3 layers)
fibrous wall with scanty inflammation

12. Eruption cyst in soft tissue over tooth about to erupt
from enamel organ (superficial dent. cyst)
children
teeth with no predecessors
soft bluish swelling in gingiva
spontaneously disappear

13. Gingival cysts newborns (Bohn´s nodules) > 80 % of newborns
gingiva - proliferation of Serres nests
spontaneously resolve in months
midline of palate (Epstein´s pearls)
adults - rare

14. Lateral periodontal cyst
uncommon cyst beside vital tooth
from nests of Malassez ?
mandibular premolars
Mi: thin squamous epithelium + plaque-like thickenings with clear cells (glycogen)

15. Lateral periodontal cyst - variants
botryoid odontogenic cyst
multilocular variant of LPC
lower P and C, may occupy major parts of jaw, > 50 years
Mi: multilocular cyst with fibrous septa
squamous epithelium + clear cells (glycogen)
recurrence (20 %)

16. Glandular odontogenic cyst (sialo-odontogenic)
multilocular cyst
Mi: complex squamous epithelium ~ LPC and BOC + mucous cells + intraepithelial glandular spaces
recurrence (30-50 %)
diff. dg.: intraosseous mucoepidermoid carcinoma

17. Odontogenic cysts WHO classification 2005  WHO 2017
odontogenic keratocyst
 keratocystic odontogenic tumor
 odontogenic keratocyst
calcifying odontogenic cyst
 calcifying cystic odontogenic tumor
 calcifying odontogenic cyst

18. Odontogenic keratocyst
3rd most common cyst of jaw
M > F; ~ 20-30Y Y
angle of mandible (80 %)
RTG: multilocular cyst
Mi: cyst – thin squamous epithelium (5-8 layers) with wavy parakeratosis ± tiny daughter cysts in wall
PTCH1 gene alteration
recurrence (2-25 %) within first 5 years !!!
treatment: complete enucleation

19. Odontogenic keratocyst
Gorlin-Goltz syndrome
AD; PTCH gene 9q ; complete penetrance; 1 : 60,000
multiple KOT + “naevoid“ basal cell carcinomas + skeletal abnormalities + ectopic calcifications + various tumors + ocular defects
Orthokeratotic cyst
rare
RTG: monolocular cyst
Mi: orthokeratotic layer
recurrence 4 %

20. Calcifying odontogenic cyst
= Gorlin´s cyst
M ~ F, ~ Y
mandible ~ maxilla, incisor-cuspid area, gingiva
Mi: cyst lined by ameloblastic epithelium
ghost cells  calcification
dentin
recurrence (5 %)
sometimes association with ameloblastoma
treatment: enucleation

21. Odontogenic cysts RTG diff. dg. of jaw radiolucency wall thickenings
anatomical structures (maxillary sinus, foramina)
odontogenic cysts
odontogenic tumors, part. ameloblastoma
giant cell granuloma / cherubism
wall thickenings
cholesterol clefts + granulomas
carcinoma
ameloblastoma

22. Odontogenic cysts daily biopsy practice
nonspecific findings – inflammation !!!
x odontogenic keratocyst
x calcifying odontogenic cyst
x unicystic ameloblastoma
x other cystic tumors

23. Nasopalatine duct cyst
uncommon, often asymptomatic
from nasopalatine duct epithelium
midline of palate
position variants (to incisive canal)
nasopalatine
palatine papilla
median alveolar
Mi: squamous + respiratory epithelium
wall: mucous glands + neurovascular bundle
enucleation

24. Nasolabial cyst = Klestadt´s, nasoalveolar very uncommon
middle-aged females
from remnants of nasolacrimal duct
in soft tissue deep in nasolabial fold
excision

25. Surgical ciliated cyst
maxilla
site of injury or operation (incl. extraction)
Caldwell-Luc surgery
cyst lining = mucosa of maxillary sinus
respiratory epithelium
enucleation

26. Cysts of soft tissues thyroglossal duct cyst lymphoepithelial cyst
lingual dermoid
mucocele

27. Thyroglossal duct cyst
uncommon
from remnants of any part of thyroglossal duct
early age
swelling in midline of mouth (foramen caecum) or neck
Mi: squamous + respiratory epithelium
wall: thyroid tissue, chronic inflammation
removal + part of hyoid bone

28. Lymphoepithelial cyst
branchiogenic cyst ???
cystic change of epithelium entrapped in LN
early age
lateral part of neck + mandible angle + parotid
soft swelling
fistula to skin / oral cavity / pharynx
Mi: squamous + respiratory epithelium
wall: dense lymphoid tissue + germ centres
enucleation
diff. dg.: cystic metastasis of SCC !!!

29. Sublingual dermoid
developmental anomaly of branchial arches or pharyngeal pouches
between hyoid and jaws or beneath tongue
no symptoms
Mi: epidermoid cyst – NO dermal appendages
dermoid cyst – dermal appendages
dissection

30. Mucoceles  minor salivary glands  lower lip
superficial, 1 cm swellings
extravasation type – damage of duct
saliva leak  inflammation + mucophages
NO epithelium  mucofagic granuloma
retention type – obstruction of duct
epithelium of dilated duct

31. Mucoceles ranula (Lat. “small frog“)
= mucocele of submandibular or sublingual gland
unilateral painless swelling, 2-3 cm
floor of mouth