Osteoma, Enostoma, Osteoid Osteoma, Osteoblastoma Flashcards
What are osteomas comprised of?
dense cortical bone
(arise from surface of bone)
What is the preferential location of osteomas?
above C1
- skull
- mandible
- sinuses (frontal, maxillary, ethmoid, sphenoid, mastoid)
What is a potential complication of an osteoma?
sinusitis if formed in sinus
causes sinus/facial/head pain & pressure due to obstruction
What is the clinical presentation of an osteoma?
most are asymptomatic
What are the radiographic features of an osteoma?
- usually solitary
- densely blastic mass (sclerotic)
- well-defined borders
What are enostomas comprised of?
woven bone
What is the preferential location of enostomas?
non-skull:
- medullary cavity
- epiphyseal, metaphyseal
- long bone surfaces
Enostomas are also called ____ OR ____ of bone
- bone island
- hamartoma
What does “hamartoma” mean?
abnormal/disorganized growth comprised of the same tissue (normal tissue) from which it grows
How would you differentiate an enostoma from blastic metastasis?
Mets:
- ^ESR
- bone scan shows “hot” areas of blastic activity
- plural
- older age
Enostoma:
- solitary
- younger age
How does an enostoma appear on a bone scan and why?
appears normal because enostoma is comprised of normal tissue, just disorganized (no increase in blastic activity)
(occasionally warm on bone scan)
Bone islands are comprised of ____ bone, located in ____ space
- woven
- trabecular
What age group is primarily affected by bone islands?
any age
Adults > children
What is the clinical presentation of an enostoma?
asymptomatic
What are the radiographic features of an enostoma?
- usually solitary, radiopaque
- round/oval, long axis aligned w/ wt-bearing trabeculae (stress lines)
- bone island >2cm
What CT finding is associated with an enostoma?
radiating (brush) border
If you see a bone island in an older patient, what must be ruled out first? What additional follow-up is needed?
blastic mets
need labs & bone scan
The center of an osteoid osteoma is called a ____
nidus
What age group is primarily affected by osteoid osteomas?
10-25 yrs
(most in teens)
What bones are capable of forming an osteoid osteoma?
any bone that formed via endochondral ossification
What is the preferential location of osteoid osteoma?
- femur or tibia (50%)
(10% in neural arch of spine) - cortically based
- metaphyseal & diaphyseal
How large is a typical nidus?
<1 cm
How does an osteoid osteoma appear radiographically?
- radiolucent lesion (nidus)
- surrounding sclerosis
What type of periosteal reaction is seen in an osteoid osteoma?
solid (surrounding sclerosis)
What part of a nidus may be ossified?
trabeculae in center (more mature)
How would a patient with an osteoid osteoma present clinically?
- adolescent w/ insidious onset
- pain at night (fewer distractions; can behave similar to fatigue Fx in adolescents)
- pain relieved by aspirin (not by Advil/Tylenol)
What type of periosteal reaction would occur in a fatigue fracture?
solid
How might you differentiate a fatigue fracture from osteoid osteoma if unsure about an x-ray?
CT scan -> gives good bony definition, can see nidus clearly through periosteal Rxn
How is an osteoid osteoma treated?
removal of nidus via En Bloc excision
How would an osteoid osteoma appear on CT?
central calcific fleck
How would an osteoid osteoma appear on a bone scan?
positive: double density sign
What is on your list of differential diagnoses for an adolescent with insidious onset of pain?
- fatigue Fx
- osteoid osteoma
- osteoblastoma
- Brodie abscess
What is the number 1 cause of a solid periosteal reaction?
fatigue Fx
What is the clinical presentation of an osteoid osteoma in the spine?
painful scoliosis
What side of scoliosis would an osteoid osteoma be found on?
concave side (bend toward side of pain)
What are the radiographic features of an osteoid osteoma in the spine?
densely blastic:
- pedicle
- lamina
- facet
What age group is primarily affected by osteoblastoma?
<20 yrs
What is an osteoblastoma comprised of?
(similar to osteoid osteoma)
osteoblasts lay down osteoid
What is the preferential location of osteoblastoma?
- spine: SP, TP, laminae (post. elements)
- C4, C5, C6 common
- TL
- metaphysis, diaphysis of long bones (LE MC, dorsal surface of talus)
How large is a typical osteoblastoma in the extremities?
> 2cm diameter (progressive enlargement)
How does osteoblastoma in the spine appear radiographically?
- radiolucent lesion (geo. lytic) without sclerotic reaction
- expansile lesion of neural arch (4-6cm)
- thin cortex
What are the differential diagnoses for osteoblastoma in the spine?
(Alphabet soup)
ABC
GCT
What pattern of destruction is seen in osteoblastoma?
geographic lytic
What type of periosteal reaction is seen in an osteoblastoma?
none
How does osteoblastoma in the extremities appear radiographically?
- lytic & expansile
- radiolucent nidus (>2cm) limited sclerosis
- sparing of epiphysis
What are the differential diagnoses for osteoblastoma in the extremities?
Osteoid osteoma
ABC
Brodie abscess
What is the clinical presentation of an osteoblastoma?
- insidious onset
- pain unresponsive to aspirin (takes much larger dose due to ^size of lesion) and not nocturnal
- swelling, palpable mass
- TS or LS lesion present w/ painful scoliosis (>50%)
- possible spinal stenosis
How is an osteoblastoma treated?
(similar to osteoid osteoma)
- wide/en bloc excision via curette (not preferred)
- radiofrequency ablation -> electric probe inserted to liquify tumor (“microwaves” tumor)
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
C
What is the most likely diagnosis?
Osteoid osteoma
What is the most likely diagnosis?
Enostoma (bone island)
What is the diagnosis?
Osteoma
What is the diagnosis? What bone is involved?
Osteoma of the mandible
What symptoms might this patient present with?
(Osteoma in frontal sinus)
Sinusitis
What is the diagnosis?
Osteoid osteoma
What is the diagnosis?
Osteoid osteoma
What is the diagnosis?
Osteoid osteoma
45 year old male. Give 2 differentials.
(Multiple blastic foci)
1. Blastic Mets
2. Bone island (enostoma)
What type of periosteal reaction is demonstrated? Give 2 differential diagnoses for this lesion.
Solid
1. Fatigue Fx
2. Osteoid osteoma
What would this lesion look like on a bone scan?
Double density sign
What is the diagnosis if the pathology report comes back identical to an Osteoid osteoma?
Osteoblastoma (>2cm)
(Non-aggressive in post. spine = alphabet soup DDx)
