W4 ADI

Non-Ossifying Fibroma, Simple Bone Cyst, Aneurysmal Bone Cyst

What is the general length of a Non-Ossifying Fibroma? How does this differ to a Fibrous Cortical Defect? (younger people and more common)

NOF is >2cm

FCD is <2cm

What is the typical age range of Non-Ossifying Fibroma?

8-20 years

What is the M:F ratio in Non-Ossifying Fibroma?

M 2:1 F

Is Non-Ossifying Fibroma usually symptomatic or asymptomatic?

Asymptomatic

Will you see a pathological fracture in Non-Ossifying Fibroma?

Yes- this will be symptomatic

What are the common sites in Non-Ossifying Fibroma?

• Distal tibia, knee, proximal humerus

What radiological features are seen in Non-Ossifying Fibroma?

• Solitary

• Eccentric location

• Soap bubbly (Multiocular)

• Arises from endosteal cortex (inside cortex)

• Expands into medullary cavity

• Metaphyseal location

• Sclerotic border (narrow zone of transition)

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Tibia

• Soap bubbly

• Narrow zone of transition

• Sclerotic border

• Geographic lesion

• Slightly expansile (not typical)

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Tibia

• Sclerotic border

• Benign lesion

• Eccentric location

• Located in the metaphysis

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Tibia

• Sclerotic border

• Benign lesion

• Eccentric location

• Soap bubbly

• Narrow zone of transition

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Fibula

• geographic lesion

• Sclerotic border

• Narrow zone of transition

• Mild expansion

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Femur

• Geographic lesion

• Soap bubbly

• Sclerotic border

• Arising from endosteal surface of cortex

• Expanding into medullary lesion

• Endosteal scalloping

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Fibula

• Diaphyseal location (unusual)

• Soap bubbly

• Sclerotic border

• Possible Fx

What bone tumour is this, what bone is it in and what can be seen?

Non-Ossifying Fibroma

Scapula

• Geographic lesion

• Sclerotic border

• Narrow zone of transition

What percentage of primary benign bone tumours do Simple Bone Cyst’s make up?

3%

A simple bone cyst is a true neoplastic disorder. True/False?

False

A simple bone cyst is a fluid-filled cyst lined with fibrous tissue. True/False?

True

The cysts in Simple Bone Cyst can be multi-chambered. True/False?

True

What is the age range for Simple Bone Cyst’s?

3-14 years

What is the M:F ratio for Simple Bone Cyst’s?

M 2:1 F

Simple Bone Cyst’s are asymptomatic until fracture. True/False?

True

For those who have a Simple Bone Cyst, how many develop a pathological fracture? (Fraction)

2/3

What locations are Simple Bone Cyst’s commonly found?

• Proximal humerus and proximal femur (75%)

• Humerus 2:1 Femur

• Pelvis and calcaneus, especially after epiphyseal closure

What location within the bone do Simple Bone Cysts arise from?

• Metaphysis

• Tend to be central with long axis aligned with bone long axis

What are the radiological features of a Simple Bone Cyst?

• Contain thin septa within matrix (soap bubbly)

• Endosteal scalloping arising from expansion

• Bone expansion (not typically beyond transverse diameter of epiphyseal growth plate)

• No cortical disruption

• No periosteal response

• No soft tissue mass

• Fallen fragment sign in 10% of cases

• Calcaneal lesions have typical appearance, located in neck, having straight, vertical anterior margin with a curved posterior sign

• Geographic radiolucent lesion

• Broad at metaphyseal end and narrow at diaphyseal end

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Metaphyseal location

• Geographic

• Soap bubbly appearance

• Narrow zone of transition

• Endosteal scalloping

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Geographic

• Slightly eccentrically located

• Mostly sclerotic border

• Can tell Pt is young, looking at growth plate

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Diaphyseal location

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Diaphyseal location

• Soap bubbly

• Non-expansile

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Pathological fracture

• Soap bubbly

• Endosteal scalloping

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Humerus

• Metaphyseal→diaphyseal location

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

Calcaneus

• Well contained

• Soap bubbly

• Sclerotic border

• Subchondral location

What bone tumour is this, what bone is it in and what can be seen?

Simple Bone Cyst

An Aneurysmal Bone Cyst is a tumour. True/False?

False (tumour-like)

An Aneurysmal Bone Cyst is a blood filled cavity. True/False?

True

When talking about Aneurysmal Bone Cyst’s, vessels are not aneurysmal. True/False?

True

What is the most common benign tumour of the clavicle?

Aneurysmal Bone Cyst

What is the age range for Aneurysmal Bone Cysts?

5-20 years

What is the M:F ratio for Aneurysmal Bone Cysts?

M 2:3 F

Will you see sudden onset of pain in Aneurysmal Bone Cysts? Yes/No?

Yes

Is there a slow or rapid increase in severity in Aneurysmal Bone Cysts?

Rapid

Pathological fractures in Aneurysmal Bone Cysts are not common. True/False?

False

In Aneurysmal Bone Cyst’s, spinal lesions can produce paraplegia. True/False?

True

There is no history of trauma in Aneurysmal Bone Cysts. True/False?

False

What are the common sites of Aneurysmal Bone Cysts?

• 80% cases occur in long tubular bones and in spine

• Femur and tibia most common long tubular bones affected

• Thoracic and lumbar spine most common spinal sites

• In spine, there is predilection for the neural arch

What areas within the bone can Aneurysmal Bone Cysts form?

• Metaphysis

• Can be Diaphysis

• Eccentric location

What are the radiological features of Aneurysmal Bone Cysts?

• Variable patterns

• Typical presentation is expansile, rapidly growing radiolucent lesion

• Overylying cortex is thinned but not broken

• Buttressing (edges of lesion usually show periosteal buttressing, similar to codman triangle)

• May show trabeculae within it- soap bubbly

• Metaphyseal into epiphysis after closure of growth plate (different to simple bone cysts that grow further away from metaphysis)

• Rarely can gross a growth plate, ONLY benign bone tumour to do this (Chordoma can- but malignant)

• Rapid growth and large size may mimic malignant tumour

• Spinal lesions are expansile, affecting neural arch, can mimic osteoblastomas

What 3 posterior arch tumours should be considered in your differentials?

• Osteoid osteoma

• Osteoid blastoma

• Aneurysmal bone cyst (will expand the most)

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Fibula

• Expansile

• Soap bubbly

• Periosteal Buttressing

• Thin cortex

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Humerus

• Metaphyseal

• Expansile

• Soap bubbly

• Periosteal buttressing

• REMEMBER→ simple bone cyst will not expand beyond bone width, can therefore rule out

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Humerus

• Soap bubbly

• Expansile

• Elongated periostea; buttressing response

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Ulna

• Not a classic appearance

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Vertebra

• Posterior arch involved

• Solitary lesion

• Expanded spinous

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Pelvis

• Periosteal buttressing

• Bone island (enostoma)

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst
Pelvis (close up of hip)

• Buttressing

• Periosteal response

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst
Posterior rib, T6

• Expansile

• Soap bubbly

• Radiolucent

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Posterior rib, T6 (close up)

• Expansile

• Soap bubbly

• Radiolucent

• Buttressing (2nd image)

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst

Clavicle

• REMEMBER→ normal not to see whole clavicle in younger people

What tumour-like condition is this, what bone is it in and what can be seen?

Aneurysmal Bone Cyst
Clavicle (close up)

• Radiolucent