Benign Bone Forming Tumors

Question 1

Osteomas are ____-growing

Answer 1

slow

Question 2

What are osteomas comprised of?

Answer 2

dense cortical bone

Question 3

What is the preferential location of osteomas?

Answer 3

skull:
- calvarial & mandibular
- sinonasal & orbital bone
- sinuses: frontal, maxillary, ethmoid, sphenoid, mastoid

Question 4

What is a potential complication of an osteoma?

Answer 4

sinusitis if formed in sinus
causes sinus pain & pressure due to obstruction

Question 5

Having multiple osteomas is implicated in what pathology?

Answer 5

Gardner syndrome
(a variant of familial adenomatous polyposis (fAPC), associated with extra-colonic features)

Question 6

What is the radiographic appearance of an osteoma?

Answer 6

• densely blastic mass
• well-defined borders

Question 7

Enostomas are ____-growing

Answer 7

slow

Question 8

What are enostomas comprised of?

Answer 8

dense cortical bone

Question 9

What is the preferential location of enostomas?

Answer 9

non-skull:
- medullary cavity
- long bone surfaces

Question 10

Enostomas are also called ____ OR ____ of bone

Answer 10

• bone island
• hamartoma

Question 11

Bone islands are comprised of ____ bone, located in ____ space

Answer 11

• dense cortical
• trabecular

Question 12

What does “hamartoma” mean?

Answer 12

abnormal/disorganized growth comprised of the same tissue from which it grows

Question 13

How would you differentiate an enostoma from blastic metastasis?

Answer 13

• ESR would be elevated if mets.
• bone scan shows “hot” areas of blastic activity if mets.

Question 14

How does an enostoma appear on a bone scan and why?

Answer 14

appears normal because enostoma is comprised of normal tissue, just disorganized (no increase in blastic activity)

Question 15

Are benign tumors considered aggressive or non-aggressive?

Answer 15

non-aggressive

Question 16

What pattern of destruction is seen in osteomas and enostomas?

Answer 16

blastic

Question 17

What is the treatment for osteomas and enostomas?

Answer 17

• clinical significance usually minimal
• surgical removal if in sensitive location

Question 18

The center of an osteoid osteoma is called a ____

Answer 18

nidus

Question 19

What is a nidus comprised of?

Answer 19

irregular trabeculae of woven bone (osteoid) within a vascular fibrous stroma containing osteoblasts & osteoclasts

Question 20

What part of a nidus may be ossified?

Answer 20

trabeculae in center (more mature)

Question 21

What age group is primarily affected by osteoid osteomas?

Answer 21

5-35 years
(most in teens)

Question 22

What bones are capable of forming an osteoid osteoma?

Answer 22

any bone that formed via endochondral ossification

Question 23

What is the preferential location of osteoid osteoma?

Answer 23

• femur or tibia (50%)
  (10% in spine)
• typically in cortical bone, may arise in medullary cavity

Question 24

How large is a typical nidus?

Answer 24

<1 cm

Question 25

How does an osteoid osteoma appear radiographically?

Answer 25

radiolucent lesion (nidus) surrounded by sclerotic bone

Question 26

What type of periosteal reaction is seen in an osteoid osteoma?

Answer 26

solid

Question 27

What pathology is associated with high levels of PGE2 in the area of the lesion?

Answer 27

Osteoid osteoma

Question 28

How would a patient with an osteoid osteoma present clinically?

Answer 28

• insidious onset
• pain at night (fewer distractions; can behave similar to fatigue Fx in adolescents)
• pain relieved by aspirin/NSAIDs

Question 29

What pathology responds to aspirin/NSAIDs and why?

Answer 29

Osteoid Osteoma
- PGE2 released causes vasodilation of vascular components in stroma
- aspirin/NSAIDs cause vasoconstriction

Question 30

What type of periosteal reaction would occur in a fatigue fracture?

Answer 30

solid

Question 31

How might you differentiate a fatigue fracture from osteoid osteoma if unsure about an x-ray?

Answer 31

CT scan -> gives good bony definition, can see nidus clearly

Question 32

What is the natural history of an osteoid osteoma?

Answer 32

• will go away with time (~2 yrs)
• pain will persist (6-8/10)

Question 33

How is an osteoid osteitis treated?

Answer 33

removal of nidus via En Bloc excision

Question 34

What is an osteoblastoma comprised of?

Answer 34

(similar to osteoid osteoma)
osteoblasts lay down osteoid

Question 35

What is the preferential location of osteoblastoma?

Answer 35

spine: laminae & pedicles (post. elements)

Question 36

How large is a typical osteoblastoma?

Answer 36

> 2cm diameter (progressive enlargement)

Question 37

How does osteoblastoma appear radiographically?

Answer 37

radiolucent lesion without sclerotic reaction

Question 38

What pattern of destruction is seen in osteoblastoma?

Answer 38

geographic lytic

Question 39

What type of periosteal reaction is seen in osteoblastoma?

Answer 39

none

Question 40

Osteoblastomas release ____ causing…

Answer 40

prostaglandins causing pain (less than osteoid osteoma)

Question 41

How does osteoblastoma respond to aspirin?

Answer 41

pain unresponsive to aspirin (takes much larger dose due to ^size of lesion)

Question 42

How is an osteoblastoma treated?

Answer 42

(similar to osteoid osteoma)
- wide/en bloc excision via curette (not preferred)
- radiofrequency ablation -> electric probe inserted to liquify tumor (“microwaves” tumor)

Question 43

If an osteoma is symptomatic, what is the most likely symptom?
A) “my hat doesn’t fit anymore”
B) visual disturbance
C) sinusitis
D) headaches

Answer 43

C