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Oral Pathology Exam 3 > 3. Odontogenic Tumors > Flashcards

3. Odontogenic Tumors Flashcards

1
Q

What is the most common Epithelial Odontogenic Tumor?

A

Ameloblastoma

(11% of odontogenic tumors)

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2
Q

What is the other name for Ameloblastoma?

A

Adamantinoma

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3
Q

What population is affected by Ameloblastomas?

A

No one is immune

  • Most cases arise on or after 3rd - 4th decade
  • But can occur in younger individuals
  • Equal M:F
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4
Q

Where are Ameloblastomas located from most to least frequently?

A
  • Posterior Mandible (77%)
  • Anterior Mandible (10%)
  • Posterior Maxilla (7%)
  • Anterior Maxilla (6%)
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5
Q

What is the clinical presentation of all Epithelial Odontogenic Tumors?

A
  • Slow growing
  • Painless
  • Bony hard swelling
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6
Q

What is the CLASSIC radiographic appearance of an Ameloblastoma? (5)

A
  • Multilocular RL, without RO
  • Fusiform/tapered mass due to expansion
  • “Eggshell” thin cortex
    • As it grows it eats away the cortex
    • If advanced it can perforate the cortex
  • Can displace teeth + resorb roots (80%)
  • Associated with an impacted tooth, usually 3rd molar (77% mandibular)
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7
Q

What is the histology of an Ameloblastoma? (3 zones)

A
  • Peripheral Zone - Hyperchromatic columnar ameloblasts “piano keys” with:
    • Subnuclear vacuolization
      • Bubbly appearing cytoplasm - defines an ameloblast
    • Reverse polarity of nuclei (toward center not CT)
  • Central Zone - of Stellate Reticulum
  • Outer Zone - of supporting stroma
    • ​Mature, collagen producing CT, not neoplastic
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8
Q

What does an Ameloblastoma’s histology reproduce?

A

Early Enamel Organ

Not going to see enamel forming because they are neoplastic ameloblasts and enamel has to have dentin first to form.

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9
Q

Where are the changes occuring in the different histologic variations of Ameloblastoma?

A

Stellate Reticulum

Doesn’t change the way it behaves or the prognosis

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10
Q

Which Histologic Variation of Ameloblastoma is the conventional type?

A

Follicular Ameloblastoma

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11
Q

Which Histologic Variation of Ameloblastoma is misken for SCCA, showing invading islands of squamous metaplasia within the SR?

A

Acanthomatous Ameloblastoma

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12
Q

In which Histologic Variation of Ameloblastoma does the SR develop cells with a granular appearance?

A

Granular Cell Ameloblastoma

Not the same cell as a granular cell tumor or congenital epulis

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13
Q

Which Histologic Variation of Ameloblastoma has no SR, it just looks like a proliferation of dental lamina that hasn’t matured to the appearance of an enamel organ?

A

Plexiform Ameloblastoma

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14
Q

Which Histologic Variation of Ameloblastoma is mistaken for Metastatic Cancers and Salivary Gland Tumors?

A

Plexiform Ameloblastoma

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15
Q

What histologically occurs in Desmoplastic Ameloblastoma?

A
  • Cells of a tumor cause the CT to become fibrous, collagenous, and dense
  • The dense CT squeezes the epithelial component
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16
Q

Where does a Desmoplastic Ameloblastoma occur?

A

Anterior Maxilla

Least common area for an Ameloblastoma

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17
Q

How is the radiographic appearance of a Desmoplastic Ameloblastoma different from the Follicular type?

A

NOT Purely RL

  • Has some “ground glass” opacification
    • Only variant with RO
  • Due to dense collagen production
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18
Q

What is the histogenesis of Ameloblastomas? (3)

A
  • Originate from residual pluripotential dental lamina rests, developing enamel organ, or the lining of Dentingerous Cyst
  • The cells are primitive with unrestrained growth
  • They are not capable of inducing dentin or production of enamel
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19
Q

What other lesions do Ameloblastoma’s have a relationship with? (5)

A
  • Basal Cell Carinoma
  • Tibial Adamanthinoma
  • Craniopharyngioma
  • Peripheral Ameloblastoma
  • Unicystic Ameloblastoma
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20
Q

What does a Tibial Adamanthinoma histologicall resemble?

A

Plexiform Ameloblastoma

But it is a malignant tumor derived from sweat glands

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21
Q

Why does a Craniopharyngioma precisely resemble the histo of an Ameloblastoma?

A

Ameloblastoma of the Pituitary Area

  • It is derived from the craniopharyngeal duct from the posterior stomodeum (oral cavity) that goes upward to form the pituitary
  • The surround tissue will be brain tissue, not collagen
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22
Q

What characterisizes the appearance of a Peripheral Ameloblastoma?

A
  • Ameloblastoma arising in the gingiva WITHOUT primary bone involvement
    • ​It may erode and secondarily infect bone, causing a slight RL.
  • Produces a GUM BUMP (4 common in DD)​
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23
Q

Where does a peripheral ameloblastoma arise from?

A

Soft tissue lesion, arising from surface epithelium

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24
Q

What is included in the DD for a Peripheral Ameloblastoma?

A

Gum Bumps

  • Pyogenic Granuloma
  • Peripheral Giant Cell Granuloma
  • Fibroma/Fibrous Hyperplasia
  • Peripheral Ossifying Fibroma
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25
Q

What is the treatment and prognosis for a Peripheral Ameloblastoma?

A
  • Doesn’t act like a typical AB, it isn’t as nasty, and it isn’t very aggressive
  • Recurrence in ~17%
    • Can be cured by a wider re-excision
    • Recurrences must be removed
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26
Q

What is the histology of the Peripheral AB?

A

Can look like any normal subtype of AB

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27
Q

What is the Histogenesis of a Unicystic Ameloblastoma?

A
  • Arises as a cyst whose lining shows:
    • SR over a basal layer of hyperchromatic ameloblasts
    • Not infiltrative like AB
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28
Q

What is the population affected by Unicystic AB?

A

Peaks in teenagers

Typical AB is 3rd-4th decade

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29
Q

Where are Unicystic ABs formed?

A

90% form around the crown of an unerupted mandibular molar

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30
Q

What is the radiographic appearance of a Unicystic AB?

A
  • Unilocular, well-demarcated RL
    • Not multilocular like AB
  • Symmetrical like a “big egg”
  • Hyper-ostotic border around periphery
  • Can get enormous, but is slow to invade
    • Can take up entire ramus and thin out the mandible
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31
Q

What is the prognosis of a Unicystic AB?

A

30% recurrence with curettage

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32
Q

What are the characteristics of Ameloblastic Carcinoma? (3)

A
  • Histo shows a growth pattern like AB but, the cells are:
    • Pleomorphic
    • High mitotic activity
    • Fast growth
  • Metastasize
  • RL lesions
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33
Q

What are the characteristics of Malignant Ameloblastoma? (2)

A
  • Perfectly benign histology
  • But metastasizes to lungs
    • This is the only way to dx it
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34
Q

What is the prognosis for Ameloblastoma?

A
  • Aggressive and recurs in 55% of attempted cures, no matter what tx method was used
  • > 5 yrs follow-up needed, because they are slow growing
  • Maxillary = more aggressive
    • Can be mutilating and impossible to tx if it spreads from the ethmoid’s –> sinus –> brain
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35
Q

What is the rule for treating an Ameloblastoma of the Mandible?

A
  • Marginal Resection
    • Resect 1 cm of radiographically normal cancellous bone and SPARE CORTEX if not involved
    • Leave the integrity of the bone
  • Segemental Block Resection ​
    • Perforated cortex mandates this
    • Lose continuity of mandible
  • Some may prefer to currete mandibular tumors, yeilding a smaller marginal resection
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36
Q

What is the rule for treating an Ameloblastoma of the Posterior Maxilla?

A
  • NEVER Curettage because recurrence is inevittable and unmanageable
  • Must resect with wide margin up to and including hemi-maxillectomy
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37
Q

Why is the Adenomatoid Odontogenic Tumor (Adenoameloblastoma) called the 2/3rds tumor?

A
  • 2/3 Female
  • 2/3 Maxilla (mostly anterior)
    • Never past premolar region
  • 2/3 10-20 y.o.
    • Not seen past the age of 25
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38
Q

What teeth are 75% of AOTs associated with?

A

Impacted tooth, usually canine

39
Q

What is the histogenesis of the adenomatoid odontogenic tumor? (3)

A
  • Derived from enamel organ
  • Cells programmed for necrobiosis
    • Cells grow to a certain point then involute, causing self-destruction of the tumor
  • Burnt-out cases
    • Tumor amyloid (stains pink)
    • Dystrophic calcification
40
Q

What is the CLASSIC radiographic appearance of Adenomatoid Odontogenic Tumor? (4)

A
  • Pericoronal RL around an impacted maxillary canine
  • Expansile and well-demarcated
  • Originate/attaches to the tooth higher along the root surface
    • Not crown-root junction like in a dentingerous cyst
  • Flecks of RO - represent dystrophic calcifications from older cells dying
41
Q

What is the histology of an AOT? (3)

A
  • Sheets of cuboidal and low columnar cells, arranged in solid and hallow cell balls separated by spindly cells
  • No CT or Stroma, just epithelium
  • Ultimately, epithelium degenerates into amyloid and dystrophic calcification
42
Q

What is the treatment and prognosis for AOT? (3)

A
  • Simple currettage is curative
  • No known recurrences, even if incompletely removed
    • Its already trying to kill itself = necrobiosis
  • Most respond spontaneously, leaving only small flecks of calcification
43
Q

What are the similarities between Calcifying Epithelial Odontogenic Tumor (Pindborg) and Ameloblastoma? (5)

A
  • Infiltrative epithelial tumor, resembling Stratum Intermedium of the enamel organ
  • Slow growing, painless bulge
  • Can be destructive
  • 3rd - 5th decade
  • Equal M:F
44
Q

What is the main difference between the Pindborg Tumor and AB?

A

Pindborg is NEVER Malignant

45
Q

Where are Calcifying Epithelial Odontogenic Tumors (Pindborg Tumor) located? (3)

A
  • Mandibular premolar region
  • 30% occur in maxilla
  • Often associtated with impacted 3rd molar
    • Like AB
46
Q

What is the radiographic appearance of the Calcifying Epithelial Odontogenic Tumor?

A
  • Multilocular or unilocular RL, occasionally with large RO
    • Completely differs from AB
47
Q

What are the histologic clues used to diagnose the Pindborg Tumor? (4)

A
  • Mature cytoplasm
  • Absence of mitoses
  • Leisegang Rings (dystrophic calcifications)
  • In the jaw

Infiltrative sheets, islands, and nests of pink squamous cells, showing hyperchromatis, pleomorphism, and coarse chromatin

48
Q

What is the best stain to use on Pindborg Tumors, and why?

A

Thioflavin T Stain

Green = amyloid

  • Epithelium undergoes necrobiosis and is replaced by dystrophic calcifications and amyloid
    • Just like AOT
49
Q

What is the treatment and prognosis for the Pindborg Tumor?

A
  • Block resection
    • ​More conservative than AB
  • 15% recurrence instead of 55% with AB
50
Q

In what population are Calcifing Odontogenic Cysts (Gorlin Cysts) common in?

A

Any age or gender

51
Q

Where are Calcifing Odontogenic Cysts (Gorlin Cysts) common?

A

Any location, preferrence for anterior areas

15% are peripheral gingival masses

52
Q

What is the radiographic presentation of the Calcifing Odontogenic Cysts (Gorlin Cysts)? (5)

A
  • CLASSICALLY a unilocular well-defined RL
  • 40% have RO dystrophic calcifications
    • ​Like AOT, Pindborg
  • 1/3 associated with an unerupted tooth, usually a canine
    • Like AOT
  • Often causes root resorption if it gets close to another tooth
    • Like AB
  • 20% are associated with Odontomas
53
Q

What is the histology of a Calcifing Odontogenic Cyst (Gorlin Cyst)

A
  • Cyst lined by epithelium aka true cyst
  • Ameloblastic lining with ghost (keratin) cells (have no nuclei) in stellate reticulum

Ameloblastoma with ghost cells

54
Q

What other tumor most resembles the Calcifying Odontogenic Cyst (Gorlin Cyst)?

A

Craniopharyngioma

55
Q

What is the treatment and prognosis of the Gorlin Cyst? (3)

A
  • Enucleation (shell it out) usually curative
  • Very few recurrences
  • If malignant often recur and can mets
    • Occasional cases are malignant but it is rare
56
Q

Odontogenic Myxoma is an invasive, infiltrative tumor, derived from , resembling .

A

Ectomesenchyme

Dental Papilla

57
Q

What is the peak age for Odontogenic Myxoma?

A

3rd decade

58
Q

What is the location of Odontogenic Myxomas?

A
  • Preference for mandible and posterior regions
  • But may occur anywhere in tooth-bearing location
59
Q

What acts like Ameloblastoma radiographically and clinically?

A

Odontogenic Myxoma

  • X-ray
    • Multilocular or soap-bubble RL
    • Fusiform expansion
    • Thins cortex and may perforate
  • Clinically
    • Slow, painless expansion
    • Can move and resorb teeth
      • Gorlin cyst also resorbs teeth
60
Q

What is the gross appearance of an Odontogenic Myxoma?

A
  • Solid, soft, gelatinous, mucoid, glary tumor,
  • “Oyster”

Differs from AB, which is part cystic and part solid

61
Q

What is the histological appearance of an Odontogenic Myxoma?

A
  • Stellate fibroblast cells,“whispy”
  • Widely separated by ground substance that stains for hyaluronic acid
    • Alcian Blue Stain = baby blue
  • Resembles histo of dental pulp, it looks like there is nothing there.
    • AB ~ early enamel organ, with lots of cells
62
Q

What is the treatment for an Odontogenic Myxoma?

A
  • Marginal or Segmental Resection
    • Like the tx for AB, but not as aggressive
63
Q

What is the prognosis for an Odontogenic Myxoma?

A
  • Goopy, gelatinous material tends to spill into the surgical bed, inviting 25% recurrences
    • < 1/2 of AB
  • No Malignancies
  • Long-term follow-up needed > 5 yrs, due to slow growth
64
Q

What does Cementoblastoma resemble histologically?

A

Osteoblastoma

Radiating trabeculae of parallel cementum lined by layers of plump cementoblasts

65
Q

What is the peak age to find a Cementoblastoma?

A

2nd - 3rd decade

Male = Female

66
Q

Where are Cementoblastomas located?

A
  • Mandible, always attached to the root, of mostly 1st molars
  • Occasionally in other molars or premolars
  • NEVER in anterior teeth
67
Q

What are the clinical symptoms of a Cementoblastoma?

A
  • PAIN to percussion and swelling
    • One of the only ones that cause pain
    • Due to being attached to the root
  • Can cause expansion due to being in the area of the alveolar bone
68
Q

What is the radiographic definitive diagnosis for a Cementoblastoma? (3)

A
  • Well-demarcated, ovoid, spherical, central RO with a thin peripheral RL rim
  • Surrounds and incorporates the root so that part of the root tends to disappear into the lesion
    • NOT root resorption
  • Radiating “sunburst” appearance, may or may not be present
    • Complex Odontomas, but they are 1st - 2nd decade
69
Q

What is the prognosis for a Cementoblastoma?

A
  • Recurrence unexpected if the tumor mass and tooth are cleanly removed
    • The tooth will probs come out when the tumor mass is removed
  • If the tooth remains there is a 20% recurrence, because they are true neoplasms
70
Q

What is in the differential diagnosis for a RO around the roots of teeth? (3)

A
  • Cementoblastoma
  • Condensing Osteitis
    • _​_Also favors mand 1st molar
    • Differs from CB:
      • Irregular outline
      • Pure homogenous RO, no RL rim or sunburst
      • Root outline visable
      • Tx = leave alone
  • Osseous Dysplasia
    • Also a mixed RL/RO, and periapical
    • Differs from CB:
      • Lower anteriors, where CB never occurs
      • Root outline visable
      • 80% in black females > 30 yrs
71
Q

List the mixed odontogenic tumors, in order of differentiation (least –> most) (4)

A
  1. Ameloblastic Fibroma
  2. Ameloblastic Fibro-Odontoma
  3. Complex Odontoma
  4. Compound Odontoma
72
Q

What are the 2 germ layers of the mixed odontogenic tumors?

A
  1. Ectoderm
  2. Ectomesenchyme
73
Q

What is the peak age of Ameloblastic Fibroma?

A

1st - 2nd decade

74
Q

List the Pediatric Odontogenic Tumors. (5)

A
  • Adenomatoid Odontogenic Tumor (AOT)
  • Unicystic Ameloblastoma
  • Ameloblastic Fibroma
  • Ameloblastic Fibro-odontoma
  • Odontomas
    • Complex
    • Compound
75
Q

What is the location for a Ameloblastic Fibroma?

A
  • 70% posterior mandible associated with an 75% unerupted molar
  • Most others in posterior maxilla
  • Uncommon in the anterior jaws
76
Q

What is the radiographic appearance of the Ameloblastic Fibroma?

A

DD for unilocular, pericoronal RL

  • Gorlin Cyst
    • Unerupted canine
  • Adenomatoid Odontogenic Tumor
    • Impacted maxillary canine
  • Pindborg Tumor
    • _​_Mandibular premolars
  • Unicystic Ameloblastoma
    • Teens, unerupted mandibular molars
77
Q

What is the Histogenesis of the Ameloblastic Fibroma? (3)

A
  • The epithelium is like that of Ameloblastoma
    • ~ Enamel organ
    • CT is the big difference:
      • Epithelium doesn’t invade the CT, the 2 germ layers grow together as a unit
      • More organized and mature than AB
  • The mesenchyme is like that of Myxoma
    • Grows with homogenous cellular stroma
      • ~ Dental papilla, no collagen
  • Usually encapsulated
78
Q

What is the treatment for an Ameloblastic Fibroma?

A
  • Marginal Resection
    • Even though it is encapsulted, shelling it out doesn’t work
  • Enucleation or currettage is discourage because of recurrence tendency
  • Don’t mess with this tumor, get it the fuck out!
79
Q

What is the prognosis for an Ameloblastic Fibroma? (2)

A
  • Tendency to recur, and if they do:
    • CT/mesenchymal portion becomes more cellular, faster growing, and more aggressive
    • But not the epithelial portion
  • Recurrences are occasionally associated with transformation to Ameloblastic Fibrosarcoma
    • Malignant and often fatal
    • ​They go after vital organs
80
Q

Why is the Ameloblastic Fibro-Odontoma more organized and mature compared to the Ameloblastic Fibroma?

A

Capable of inducing dental hard tissue (enamel, dentin, cementum)

81
Q

What is the age group affected by Ameloblastic Fibro-Odontoma?

A

5-20 yrs old (avg age = 10)

82
Q

What is the radiographic appearance of the Ameloblastic Fibro-Odontoma?

A
  • Unerupted posterior tooth
  • Pericoronal RL with RO representing dental hard tissue
    • ​1st one with RO due to actual tooth structure!
  • May get large
83
Q

What is the Histology of the Ameloblastic Fibro-Odontoma?

A

Looks like Ameloblastic Fibroma, that is producing histologically recogonizable but morphologically disoriented enamel, dentin and cementum.

84
Q

What is the prognosis for Ameloblastic Fibro-Odontoma?

A

May turn into Ameloblastic Fibrosarcoma

Remove Aggressively

85
Q

What is the most common Odontogenic Tumor?

A

Odontomas (60%)

86
Q

Characterize Odontomas. (3)

A
  • Mixed odontogenic tumor that most closely approaches normal odontogenesis
    • Dental hard tissue is formed
    • The enamel epithelium that formed it involutes
    • The tumor is encapsulated in a “dental follicle” just like a tooth would be
  • Most are asymptomatic
    • Larger cases can cause swelling and pain
  • All develop in tooth-bearing areas in the 1st - 2nd decade when teeth are forming
87
Q

When/How are Odontomas diagnosed?

A
  • During investigation of a:
    • Primary tooth that fails to exfoliate
    • Permanent tooth that fails to erupt
88
Q

What is the histology of the Complex Odontoma?

A

Honeycombed conglomeration of enamel matrix, dentin, cementum, and pulp

  • Normal Histogenesis = recognizable enamel, dentin, and cementum
  • Abnormal Morphogenesis = disorganized anatomy
    • Enamel, dentin, and cementum are not in the right place
    • Doesn’t look like a tooth
89
Q

Where are Complex Odontomas located?

A

Posterior Jaws

90
Q

What is the radiographic appearance of the Complex Odontoma? (3)

A
  • Sunburst RO, surrounded by a thin RL
  • Overlying/coronal to the tooth, it won’t even look like there is a tooth there.
  • Can be confused with an Osteoma or any other highly calcified bone lesion
91
Q

Where are Compound Odontomas located?

A

Anterior Maxilla

  • Opposite of Complex Odontoma
  • Like the AOT and Desmoplastic Ameloblastoma
92
Q

What is the histology of the Compound Odontoma?

A

Normal Histogenesis and Morphogenesis

93
Q

What is the radiographic appearance of the Compound Odontoma?

A
  • Multiple, smaller teeth = RO portion
  • RL sac surrounds

Oral Pathology Exam 3 (8 decks)

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