Bone Tumours Flashcards
GCT is more common in
Females
Female-to-male ratio, 2-1
Age of GCT
> 30 years
After epiphyseal fusion
Mature skeleton
70% occur between the 3rd and 5th decades
Typical radiographic appearance of GCT
Lytic geographic lesion Narrow zone if transition No marginal sclerosis (Type IA margin) Bone expansion Located at the end of long bones Eccentric Extension into subchondral bone No matrix May show fluid-fluid levels May have soft tissue component
What’s type IB margin?
Broader zone of transition
Can be seen occasionally in GCT
GCT’s originate from
Metaphysis
Not epiphysis, but the extend into epiphysis
Chondroblasyomas arise from epiphysis in immature skeletons
Most common locations for GCT
About the knee
Distal radius and ulna
Proximal humerus
Spine
Do GCT’s contain matrix
No
Chondroblastomas do
GCT in the spine usually involves
The sacrum
Vertebral bodies
RATHER THAN Posterior elements
Osteoblastomas and ABC’s involve the posterior elements
Most GCT’s are solitary or multiple?
Most are solitary
Can be multiple in the skull and facial bones affected by Paget’s disease mimicking metastasis
EG and FD can be multiple more commonly
Primary cell in GCT?
Spindle cell
Fallen fragment sign is pathognomonic for
Unicameral bone cyst complicated by a fracture
Periosteal reaction seen in simple bone cyst or other benign bone lesions is usually
A stress response to weakened bone
Not part of the tumor
MRI features of GCT
Low-intermediate T1
Relatively low T2
Which helps differentiating it from other subchondral lesions like subchondral cyst and Brodie’s abscess which have bright T2 signal intensity
