Causes and Risk Factors of Bone Cysts
The exact causes and risk factors of bone cysts remains somewhat unclear, especially for unicameral (simple) bone cysts. However, doctors believe that they are often related to fluid build-up and abnormal growth in the bone marrow cavity during childhood development.
1. Unicameral (simple) bone cysts
- Believed to occur due to a blockage in the normal drainage of fluid within the bone.
- This trapped fluid may accumulate and slowly form a cyst.
- These cysts are not inherited, and there is no evidence of a genetic cause.
Risk factors for simple bone cysts include:
- Age: Most common in children aged 5–15
- Sex: More frequently seen in boys than girls
- Location: Predominantly affects the proximal humerus and femur
- Rapid growth periods: May correlate with spurts in bone development
2. Aneurysmal bone cysts
- Thought to arise from abnormal blood vessel formation within the bone.
- Blood accumulates in spaces within the bone, causing pressure and expansion.
- Some cases occur after trauma, though the link isn’t fully understood.
Risk factors for aneurysmal bone cysts:
- Previous injury to the bone or surrounding tissue
- Presence of other benign bone tumours, like giant cell tumours
- More common in adolescents and young adults
- Slightly more common in females
3. Genetic and pathological associations
- In rare cases, aneurysmal bone cysts may have a genetic mutation linked to the USP6 gene.
- These cysts are not typically inherited but result from spontaneous cellular changes.
Causes and Risk Factors of Bone Cysts
Environmental or lifestyle causes are not linked to bone cysts, and they cannot be prevented. However, timely diagnosis and monitoring ensure they do not lead to complications, especially pathological fractures in active children.
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