3. Odontogenic Tumors Flashcards
(93 cards)
1
Q
What is the most common Epithelial Odontogenic Tumor?
A
Ameloblastoma
(11% of odontogenic tumors)
2
Q
What is the other name for Ameloblastoma?
A
Adamantinoma
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
4
Q
Where are Ameloblastomas located from most to least frequently?
A
- Posterior Mandible (77%)
- Anterior Mandible (10%)
- Posterior Maxilla (7%)
- Anterior Maxilla (6%)
5
Q
What is the clinical presentation of all Epithelial Odontogenic Tumors?
A
- Slow growing
- Painless
- Bony hard swelling
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)
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)
-
Subnuclear vacuolization
- Central Zone - of Stellate Reticulum
-
Outer Zone - of supporting stroma
- Mature, collagen producing CT, not neoplastic
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.
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
10
Q
Which Histologic Variation of Ameloblastoma is the conventional type?
A
Follicular Ameloblastoma
11
Q
Which Histologic Variation of Ameloblastoma is misken for SCCA, showing invading islands of squamous metaplasia within the SR?
A
Acanthomatous Ameloblastoma
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
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
14
Q
Which Histologic Variation of Ameloblastoma is mistaken for Metastatic Cancers and Salivary Gland Tumors?
A
Plexiform Ameloblastoma
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
16
Q
Where does a Desmoplastic Ameloblastoma occur?
A
Anterior Maxilla
Least common area for an Ameloblastoma
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
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
19
Q
What other lesions do Ameloblastoma’s have a relationship with? (5)
A
- Basal Cell Carinoma
- Tibial Adamanthinoma
- Craniopharyngioma
- Peripheral Ameloblastoma
- Unicystic Ameloblastoma
20
Q
What does a Tibial Adamanthinoma histologicall resemble?
A
Plexiform Ameloblastoma
But it is a malignant tumor derived from sweat glands
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
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)
23
Q
Where does a peripheral ameloblastoma arise from?
A
Soft tissue lesion, arising from surface epithelium
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
25
What is the treatment and prognosis for a Peripheral Ameloblastoma?
* 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**
26
What is the histology of the Peripheral AB?
Can look like any normal subtype of AB
27
What is the Histogenesis of a Unicystic Ameloblastoma?
* Arises as a **cyst** whose lining shows:
* SR over a basal layer of **hyperchromatic ameloblasts**
* *Not infiltrative like AB*
28
What is the population affected by Unicystic AB?
Peaks in **teenagers**
## Footnote
*Typical AB is 3rd-4th decade*
29
Where are Unicystic ABs formed?
90% form around the **crown** of an **unerupted mandibular molar**
30
What is the radiographic appearance of a Unicystic AB?
* **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
31
What is the prognosis of a Unicystic AB?
**30% recurrence** with curettage
32
What are the characteristics of Ameloblastic Carcinoma? (3)
* Histo shows a growth pattern like AB but, the cells are:
* Pleomorphic
* High mitotic activity
* Fast growth
* Metastasize
* RL lesions
33
What are the characteristics of Malignant Ameloblastoma? (2)
* Perfectly **benign histology**
* But **metastasizes to lungs**
* This is the only way to dx it
34
What is the prognosis for Ameloblastoma?
* **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_
35
What is the rule for treating an Ameloblastoma of the Mandible?
* _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*
36
What is the rule for treating an Ameloblastoma of the Posterior Maxilla?
* **NEVER Curettage** because recurrence is inevittable and unmanageable
* **Must resect** with **wide margin** up to and including **hemi-maxillectomy**
37
Why is the Adenomatoid Odontogenic Tumor (Adenoameloblastoma) called the 2/3rds tumor?
* **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
38
What teeth are 75% of AOTs associated with?
**Impacted** tooth, usually **canine**
39
What is the histogenesis of the adenomatoid odontogenic tumor? (3)
* 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
What is the CLASSIC radiographic appearance of Adenomatoid Odontogenic Tumor? (4)
* **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
What is the histology of an AOT? (3)
* 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
What is the treatment and prognosis for AOT? (3)
* **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
What are the similarities between Calcifying Epithelial Odontogenic Tumor (Pindborg) and Ameloblastoma? (5)
* Infiltrative epithelial tumor, resembling **Stratum Intermedium** of the **enamel organ**
* **Slow growing, painless** bulge
* Can be **destructive**
* **3rd - 5th decade**
* Equal M:F
44
What is the main difference between the Pindborg Tumor and AB?
Pindborg is NEVER Malignant
45
Where are Calcifying Epithelial Odontogenic Tumors (Pindborg Tumor) located? (3)
* **Mandibular premolar region**
* 30% occur in maxilla
* Often associtated with **impacted 3rd molar**
* *Like AB*
46
What is the radiographic appearance of the Calcifying Epithelial Odontogenic Tumor?
* **Multilocular _or_ unilocular RL**, occasionally with **large RO**
* *Completely differs from AB*
47
What are the histologic clues used to diagnose the Pindborg Tumor? (4)
* Mature cytoplasm
* Absence of mitoses
* **Leisegang Rings** (dystrophic calcifications)
* In the jaw
## Footnote
*Infiltrative sheets, islands, and nests of pink squamous cells, showing hyperchromatis, _pleomorphism_, and coarse chromatin*
48
What is the best stain to use on Pindborg Tumors, and why?
**Thioflavin T Stain**
Green = amyloid
* Epithelium undergoes **necrobiosis** and is replaced by dystrophic calcifications and amyloid
* *Just like AOT*
49
What is the treatment and prognosis for the Pindborg Tumor?
* **Block resection**
* _More conservative_ than AB
* **15% recurrence** instead of 55% with AB
50
In what population are Calcifing Odontogenic Cysts (Gorlin Cysts) common in?
Any age or gender
51
Where are Calcifing Odontogenic Cysts (Gorlin Cysts) common?
Any location, preferrence for **anterior areas**
**15%** are **peripheral gingival masses**
52
What is the radiographic presentation of the Calcifing Odontogenic Cysts (Gorlin Cysts)? (5)
* 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
What is the histology of a Calcifing Odontogenic Cyst (Gorlin Cyst)
* Cyst lined by epithelium aka **true cyst**
* Ameloblastic lining with **ghost (keratin) cells** (have no nuclei) in **stellate reticulum**
## Footnote
*Ameloblastoma with ghost cells*
54
What other tumor most resembles the Calcifying Odontogenic Cyst (Gorlin Cyst)?
Craniopharyngioma
55
What is the treatment and prognosis of the Gorlin Cyst? (3)
* **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
Odontogenic Myxoma is an invasive, infiltrative tumor, derived from , resembling .
Ectomesenchyme
Dental Papilla
57
What is the peak age for Odontogenic Myxoma?
3rd decade
58
What is the location of Odontogenic Myxomas?
* Preference for **mandible** and **posterior regions**
* But may occur _anywhere in tooth-bearing location_
59
What acts like Ameloblastoma radiographically and clinically?
**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
What is the gross appearance of an Odontogenic Myxoma?
* Solid, **soft**, gelatinous, mucoid, glary tumor,
* **"Oyster"**
Differs from AB, which is part cystic and part solid
61
What is the histological appearance of an Odontogenic Myxoma?
* **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
What is the treatment for an Odontogenic Myxoma?
* **Marginal** or **Segmental Resection**
* Like the tx for AB, but not as aggressive
63
What is the prognosis for an Odontogenic Myxoma?
* **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
What does Cementoblastoma resemble histologically?
**Osteoblastoma**
Radiating trabeculae of parallel cementum lined by layers of plump cementoblasts
65
What is the peak age to find a Cementoblastoma?
**2nd - 3rd decade**
Male = Female
66
Where are Cementoblastomas located?
* **Mandible**, always **attached to the root**, of mostly **1st molars**
* Occasionally in other molars or premolars
* NEVER in anterior teeth
67
What are the clinical symptoms of a Cementoblastoma?
* **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
What is the radiographic definitive diagnosis for a Cementoblastoma? (3)
* 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
What is the prognosis for a Cementoblastoma?
* 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
What is in the differential diagnosis for a RO around the roots of teeth? (3)
* _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
List the mixed odontogenic tumors, in order of differentiation (least --\> most) (4)
1. Ameloblastic Fibroma
2. Ameloblastic Fibro-Odontoma
3. Complex Odontoma
4. Compound Odontoma
72
What are the 2 germ layers of the mixed odontogenic tumors?
1. Ectoderm
2. Ectomesenchyme
73
What is the peak age of Ameloblastic Fibroma?
1st - 2nd decade
74
List the Pediatric Odontogenic Tumors. (5)
* Adenomatoid Odontogenic Tumor (AOT)
* Unicystic Ameloblastoma
* Ameloblastic Fibroma
* Ameloblastic Fibro-odontoma
* Odontomas
* Complex
* Compound
75
What is the location for a Ameloblastic Fibroma?
* **70% posterior mandible** associated with an **75%** **unerupted molar**
* Most others in **posterior maxilla**
* Uncommon in the anterior jaws
76
What is the radiographic appearance of the Ameloblastic Fibroma?
**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
What is the Histogenesis of the Ameloblastic Fibroma? (3)
* 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
What is the treatment for an Ameloblastic Fibroma?
* **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
What is the prognosis for an Ameloblastic Fibroma? (2)
* **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
Why is the Ameloblastic Fibro-Odontoma more organized and mature compared to the Ameloblastic Fibroma?
Capable of **inducing dental hard tissue** (enamel, dentin, cementum)
81
What is the age group affected by Ameloblastic Fibro-Odontoma?
5-20 yrs old (avg age = 10)
82
What is the radiographic appearance of the Ameloblastic Fibro-Odontoma?
* Unerupted posterior tooth
* **Pericoronal RL** with **_RO representing dental hard tissue_**
* *1st one with RO due to actual tooth structure!*
* May get large
83
What is the Histology of the Ameloblastic Fibro-Odontoma?
Looks like Ameloblastic Fibroma, that is producing _histologically recogonizable_ but **_morphologically disoriented_** enamel, dentin and cementum.
84
What is the prognosis for Ameloblastic Fibro-Odontoma?
May turn into ***Ameloblastic Fibrosarcoma***
## Footnote
**Remove Aggressively**
85
What is the most common Odontogenic Tumor?
Odontomas (60%)
86
Characterize Odontomas. (3)
* 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
When/How are Odontomas diagnosed?
* During investigation of a:
* **Primary tooth** that **fails to exfoliate**
* **Permanent tooth** that **fails to erupt**
88
What is the histology of the Complex Odontoma?
**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
Where are Complex Odontomas located?
Posterior Jaws
90
What is the radiographic appearance of the Complex Odontoma? (3)
* **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
Where are Compound Odontomas located?
**Anterior Maxilla**
* Opposite of *Complex Odontoma*
* Like the *AOT* and *Desmoplastic Ameloblastoma*
92
What is the histology of the Compound Odontoma?
Normal Histogenesis and Morphogenesis
93
What is the radiographic appearance of the Compound Odontoma?
* **Multiple, smaller teeth** = RO portion
* **RL sac surrounds**
