CH15- Mixed Odontogenic Tumors

Question 1

What are the 6 mixed (epithelial and ectomesenchymal) odontigenic tumors?

Answer 1

1.ameloblastic fibroma 2.ameloblastic fibro-odontoma 3.Ameloblastic fibrosarcoma 4.Odontoameloblastoma 5. Compoound odontoma 6. Complex odontoma

Question 2

What tumor was commonly diagnosed as an early stage odontoma before it go its own name?

Answer 2

Ameloblastic fibroma

Question 3

Ameloblastic fibroma: age? sex? location?

Answer 3

Young 1st-2nd decade…slightly male, 70% in posterior mandible

Question 4

What clinical characteristic is associated with an ameloblastic fibroma 75% of the time?

Answer 4

an unerupted tooth

Question 5

Microscopically, the tumor is composed of a cell-rich mesenchymal tissue resembling the primitive dental papilla admixed with proliferating odontogenic epithelium.

Answer 5

Ameloblastic fibroma

Question 6

What are the two patterns of the epithelial component of an ameloblastic fibroma?

Answer 6

1.long narrow cords 2 cells thick of cuboidal or columnar cells OR 2. small descrete islands that look like the follicular stage of the developing enamel organ

Question 7

What is an important distinguishing feature of the epithelial islands in an ameloblastic fibroma vs an ameloblastoma?

Answer 7

AF = NO microcyst formation

Question 8

What is the REAL recurrence rate of AFs?

Answer 8

0-18%

Question 9

Recurrent AFs are at risk for what 35% of the time?

Answer 9

Ameloblastic Fibrosarcoma

Question 10

________ is a tumor with the general features of an ameloblastic fibroma but that also contains ENAMEL and DENTIN

Answer 10

Ameloblastic fibro-odontoma

Question 11

AF-O: age? location? sex?

Answer 11

10 yrs…posterior mandible…male

Question 12

AF-O: the soft tissue component is histologically identical to what?

Answer 12

Ameloblastic Fibroma

Question 13

What is the varient of ameloblastic fibro-odontoma in which there is NO enamel formation and ONLY dentin formation?

Answer 13

ameloblastic fibro-dentinoma

Question 14

What is the recurrence rate for AF-O?

Answer 14

7%

Question 15

Ameloblastic Fibrosarcoma: in most cases, which histological component looks malignant while the other remains bland?

Answer 15

the mesenchymal portion looks malignant and the epithelial portion looks bland

Question 16

Most ameloblastic fibrosarcomas are considered to be de novo, but what % arise from another entity? What are the two entities?

Answer 16

33% from ameloblastic fibroma or ameloblastic fibro-odontoma

Question 17

Ameloblastic fibrosarcoma: age? sex? location?

Answer 17

1.5 times more often for males, 27.5 years, 80% of cases in the mandible

Question 18

In some cases of ameloblastic fibrosarcoma with multiple recurrences, the epithelial component becomes progressively less conspicuous so that the tumor eventually shows only WHAT?

Answer 18

a poorly differentiated fibrosarcoma

Question 19

Woah.. in a few instances of ameloblastic fibrosarcoma, dysplastic dentin or small amounts of enamel may be formed…what are two (unnessisary) subclassification names?

Answer 19

ameloblastic dentinosarcoma..ameloblastic fibroodontosarcoma

Question 20

What is an ameloblastic fibrosarcoma that now has transformation of BOTH epithelial and mesenchymal elements?

Answer 20

ameloblastic carcinosarcoma

Question 21

Odontoameloblastoma: age? location?

Answer 21

younger…either jaw

Question 22

What does an odontoameloblastoma resemble radiographically??

Answer 22

complex odontoma

Question 23

Name that tumor: The proliferating epithelial portion of the tumor = ameloblastoma, most often of the
plexiform or follicular pattern…intermingled with immature or more mature dental tissue = compound odontoma, or complex odontoma

Answer 23

Odontoameloblastoma (no histology picture in Neville lol)

Question 24

What is the clinical significance between an odontoameloblastoma and an ameloblastic fibro-odontoma?

Answer 24

Odontoameloblastoma: same biologic potential as ameloblastoma (15-90% recurrence rate) VS ameloblastic fibro-odontoma: 7% recurrence

Question 25

The most common odontogenic tumor, prevelance exceeding all others combined…

Answer 25

odontoma

Question 26

_________ odontoma is composed of

multiple, small toothlike structures.

Answer 26

compound

Question 27

________ odontoma consists of a conglomerate mass of enamel and dentin, which bears no anatomic resemblance to a tooth.

Answer 27

complex

Question 28

________ odontomas are more frequently diagnosed than ________ , and it is possible that they are not even submitted for microscopic examination

Answer 28

compound more than complex

Question 29

Odontoma: age? location? more specific location for compound odontoma?

Answer 29

14 years….somewhat more frequently in the maxilla…compound is more in the ANTERIOR MAXILLA

Question 30

A complex odontoma can be radiographically confused with ________

Answer 30

an osteoma (just dense RO lesion)

Question 31

Complex odontomas histologically consist largely of ___________

Answer 31

mature tubular dentin

Question 32

Small islands of eosinophilic-staining epithelial

_______ cells are present in about 20% of complex odontomas.

Answer 32

ghost

Question 33

Complex odontoma: A thin layer of ________ is often present about the periphery of the mass.

Answer 33

cementum

Question 34

Occasionally, a _________ may arise from the epithelial lining of the fibrous capsule of a complex odontoma.

Answer 34

dentigerous cyst