Bone Cysts & Tumor-like Bone Pathologies Flashcards
What are alternative names for a simple bone cyst?
Unicameral or solitary bone cyst
Is a simple bone cyst neoplastic?
No
In short, what is a simple bone cyst?
Disturbance of bone growth following trauma
When in life do 80% of simple bone cysts occur?
Before age 20
Which sex more often experiences simple bone cysts?
Male > Female (3:1)
Where in the body are simple bone cysts most likely to occur?
Metaphyses of:
- Humerus
- Femur
- Tibia
How does trauma lead to a simple bone cyst?
Hematoma forms and resolves –>
Body attempts to resolve trauma and forms a fibrous lining –>
Fibrous tissue pulls serous fluid into lesion –>
Fluid pressure leads to bone resorption –>
Reactive bone formation –>
Lytic lesion with a thin, well-defined margin and sclerotic border
After trauma, the body has formed fibrous lining which pulls serous fluid into the lesion. The fluid pressure leads to bone resorption and some reactive bone formation has occurred. There is now a lytic lesion with a thin, well-defined margin and sclerotic border.
What pathology is present?
Simple bone cyst
Is a simple bone cyst a true cyst?
No, there is no distinct cell lining
A simple bone cyst is never greater in diameter to…
the growth plate
Which cells are present in a simple bone cyst?
Osteoclastic giant cells, macrophages, and chronic inflammatory cells
Osteoclasts present in advancing area of cyst
What are the radiographic clinical manifestations of a simple bone cyst?
- Unilocular radiolucent lesion with sclerotic border
- Usually centrally located
What are symptoms someone with a simple bone cyst may experience?
- Generally asymptomatic
- Pathological fracture
What are some treatments for simple bone cysts?
- Intralesional corticosteroids
- Curettage and bone grafting
- May reoccur
Aneurysmal bone cysts usually affect individuals ___ years of age
<20 years of age
What is the distribution of aneurysmal bone cysts amongst sexes?
Male = Female
If aneurysmal bone cyst is caused by USP6 overexpression, leading to increase in proteases and transcription factors that upregulate cystic resorption of bone, it is ___
primary
If aneurysmal bone cyst develops with other primary tumors such as giant cell tumors, it is ___
secondary
What makes aneurysmal bone cyst primary?
USP6 overexpression
Increased proteases and transcription factors upregulate cystic resorption of bone
What is the gross appearance of aneurysmal bone cysts?
- Multiloculated lytic lesion with septa composed of fibrous tissue and reactive bone
- Filled with blood
- Resembles a sponge permeated with blood and clots
If bone appears as a sponge permeated with blood and blood clots, what is suspected?
Aneurysmal bone cyst
Aneurysmal bone cysts grow in what nature?
- Rapidly
- Very large
- Central or eccentric
- Expansile (enlarges bone)
As aneurysmal bone cyst enlarges bone, ___ remain intact and ___ thins
periosteum and cortex remain intact and cortex thins