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dentistry in a nutshell > scr - os & histopathology - tumours > Flashcards

scr - os & histopathology - tumours Flashcards

1
Q

odontogenic tumours

A

majority asymptomatic often discovered due to:
- non eruption of teeth
- late stage bony expansion
- incidental finding
pain is usually due to pathological # or 2ndary infection

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2
Q

3 groups of odontogenic tumour

A
  1. epithelial -> ameloblastoma / adenomatoid odontogenic tumour / calcifying epithelial odontogenic tumour
  2. mesenchymal -> odontogenic myxoma
  3. mixed (both of above) -> odontoma
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3
Q

mixed tumours specifically

A

can have enamel / dentine formation due to concept of induction
1st formed dentine from odontoblasts which are mesenchymal in origin
ameloblasts mature & form enamel only when dentine starts getting laid down so present of dentine crucial for induction for maturation of ameloblast formation of enamel

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4
Q

odontogenic sources of epithelium

A

rests of malassez - from hertwig’s epithelial root sheath
rests of serres - from dental lamina
reduced enamel epithelium - from enamel organ

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5
Q

ameloblastoma

A

benign epithelial tumour
locally destructive but slow growing & typically painless
1% of OMFS tumours
4th-6th decades most common
80% posterior mandible
M>F

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6
Q

radiographic appearance of ameloblastoma

A

well defined bone surrounding pathology
well defined corticated margins
scalloped & multicystic
thick curved septa i.e. soap bubble appearance
primarily radiolucent

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7
Q

adjacent structures to ameloblastoma

A
  1. displacement; characteristic expansion pattern (expands in all directions fairly equally)
  2. thinning of bony cortices
  3. ‘knife edge’ external root resorption
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8
Q

histopathological criteria of ameloblastoma

A

can be:
follicular
plexiform
desmoplastic

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9
Q

plexiform form

A

shows fibrous tissue / stellate reticulum like tissue / ameloblast like cells
no CT capsule
so cells can grow & infiltrate into jaw bone & is one of the main reasons for high recurrence rate

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10
Q

follicular form

A

islands bordered by cells that resemble ameloblasts
tissue in middle of follicles is loose resembling stellate reticulum of tooth germ & can sometimes have cystic changes in follicle

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11
Q

management of ameloblastoma

A
  1. surgical resection with margin
  2. recurrence relatively common ~ 15%
  3. risk of malignant transformation <1% (ameloblastic carcinoma)
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12
Q

how would benign tumour appear in ultrasound (4)

A

well defined
encapsulated
peripheral vascularity
no lymphadenopathy

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13
Q

options for differential diagnosis for multilocular radiolucency in mandible

A

OKC
ameloblastoma
ameloblastic fibroma
odontogenic myxoma
odontogenic fibroma

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14
Q

follicular histopathology

A

tumour cells in follicular pattern
resemble enamel organ in developing tooth with a central mass resembling the stellate reticulum
surrounded by ameloblast like cells that display the typical reversed polarity, the nuclei are located away from the basement membrane opposite to what is usual

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15
Q

changes in the stellate area within the follicle

A

cystic breakdown - looks like large white spaces
squamous metaplasia
granular cell changes

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16
Q

plexiform histopathology

A

neoplastic epithelium arranged as a network of strands and irregular masses displaying the same cell layers as the follicular pattern with reversed polarity obvious
cyst degeneration in this type is mainly due to stromal degeneration

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17
Q

adenomatoid odontogenic tumour

A

benign epithelial tumour
3% of odontogenic tumours
most common 2nd decade
F>M
anterior maxilla

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18
Q

key about AOT

A

75% associated with u/e tooth, commonly maxillary canine

19
Q

radiographic criteria of AOT

A

unilocular radiolucency
majority have internal calcification / radiopacities which increase as tumour matures
margins well defined & corticated
may displace adjacent structures but external root resorption rare
very similar to dentigerous cyst

20
Q

difference between AOT & dentigerous cyst

A

AOT has
1. thicker cortical margins
2. attaches further down root (cyst attaches at CEJ)

21
Q

histopathological criteria of AOT

A

epithelial in origin
arranged in duct like structures (big hole) described as rosette appearance
distinctive with patchy calcification
well developed fibrous tissue capsule surrounding cells so removal of tumour straightforward surgically & recurrence rate is LOW

22
Q

calcifying epithelial odontogenic tumour

A

benign epithelial tumour
1% odontogenic tumours
most common 5th decade
M>F
posterior mandible most common
slow growing but can become large
1 in 2 associated with u/e tooth

23
Q

radiographic criteria of CEOT

A

variable presentation
uni or multi locular
well or poorly defined margins
internal septa - poor / fine / none

24
Q

odontogenic myxoma

A

mesenchymal benign tumour
3-6% of odontogenic tumours
most common in 3rd decade
F = M
Mandible > maxilla

25
Q

radiographic criteria of odontogenic myxoma

A

well defined radiolucency +/- thin corticated margin
small lesions = unilocular
large lesions = multilocular
soap bubble appearance of septa
slow growth along bone before causing buccolingual expansion
scallops between teeth but larger lesions may cause displacement; external root resorption rare

26
Q

histopathological criteria of odontogenic myxoma

A

loose myxoid tissue with stellate cells
may contain islands of inactive odontogenic epithelium
no capsule = locally invasive

27
Q

odontogenic myxoma management

A

curettage / resection depending on size
high recurrence ~ 25%
follow up important
lower recurrence rate if unilocular

28
Q

odontoma

A

benign mixed tumour
technically a hamartoma
malformation of dental tissue
1/5 - 2/3 of all odontogenic tumours
most common 2nd decade
F = M

29
Q

odontoma similarities to teeth

A

mature to certain stage
can be associated with other odontogenic lesions e.g. dentigerous cyst
surrounded by dental follicle
lie above IAN canal

30
Q

2 types of odontoma

A

complex -> disorganised mass of dental tissue, more common posterior body of mandible
compound -> ordered dental structures, may appear as multiple mini teeth, more common anterior maxilla

31
Q

radiographic criteria of odontoma

A

well defined clump of radiopaque material

32
Q

histopathological criteria of odontoma

A

both from mesenchymal & epithelial tissue
enamel is inorganic so is dissolved during process of slide development; may not show on slide dependent on level of calcification

33
Q

ossifying fibroma clinical criteria

A

slow growing
wide age range
mainly mandible
similar to fibrous dysplasia but has capsule which is reflected in radiolucent line surrounding mass whereas dysplasia blends into the bone

34
Q

histopathological criteria of ossifying fibroma

A

cellular fibrous tissue
immature bone
acellular calcifications

35
Q

fibrous dysplasia

A

slow growing asymptomatic bony swelling due to bone being replaced by fibrous tissue
active u20yrs of age
can be single or multiple bone
maxilla > mandible
can be syndromic - albright’s syndrome (melanin pigment & early puberty)

36
Q

radiographic criteria of fibrous dysplasia

A

margins often blend into adjacent bone
bone maintains approximate shape initially
becomes more radiopaque as lesion matures
can have variable appearances i.e. cotton wool / amorphous

37
Q

histopathological criteria of fibrous dysplasia

A

fibro osseous
fibrous replacement of bone
no capsule separating it from normal bone
bone remodels and increases in density

38
Q

rarefying osteitis

A

localised bone loss in response to inflammation
always occurring 2ndary to another form of pathology
if at apex of tooth consider apical periodontitis / PA granuloma / PA abscess

39
Q

sclerosing osteitis

A

localised increase in bone density in response to low grade inflammation
most common around apex of tooth with necrotic pulp
PA radiopacity often poorly defined
may eventually lead to external root resorption if chronic

40
Q

osteosarcoma

A

malignancy of bone
normally in 30s
if older generally due to paget’s
mandible > maxilla
recurrence, local destruction & metastases

41
Q

paget’s disease

A

usually >40ys
M > F
aetiology unknown
serum biochemistry shows raised alkaline phosphatase
disease of disturbed bone turnover -> deposition & resorption occur at the same time so bone becomes soft & deformed then calcifies in deformed shape

42
Q

dental changes with paget’s

A

loss of lamina dura
hypercementosis
migration (due to bone enlargement)

43
Q

histology of paget’s

A

reversal lines - indicate change in turnover which can be very darkly stained
will burn out itself
osteoclastic & osteoblastic activity

44
Q

tx of paget’s pt

A

xla of teeth can be difficult due to hypercementosis / pathological # of mandible / affected bone tends to develop osteosarcoma
dense bone harder to LA
MRONJ risk as on anti resorptives
osteosclerotic stage = less vascular so little bleeding so increased risk of dry socket / MRONJ
osteolytic stage = more vascular so lots of bleeding

dentistry in a nutshell (30 decks)

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