Aneurysmal bone cyst
|Aneurysmal bone cyst|
Signs and symptoms
The afflicted may have relatively small amounts of pain that will quickly increase in severity over a time period of 6–12 weeks.
The skin temperature around the bone may increase, a bony swelling may be evident, and movement may be restricted in adjacent joints.
Approximate percentages by sites are as shown:
- Skull and mandible (4%)
- Spine (16%)
- Clavicle and ribs (5%)
- Upper extremity (21%)
- Pelvis and sacrum (12%)
- Femur (13%)
- Lower leg (24%)
- Foot (3%)
Aneurysmal bone cyst has been widely regarded a reactive process of uncertain cause since its initial description by Jaffe and Lichtenstein in 1942.
Many hypotheses have been proposed to explain the cause and pathogenesis of aneurysmal bone cyst, and until very recently the most commonly accepted idea was that aneurysmal bone cyst was the consequence of an increased venous pressure and resultant dilation and rupture of the local vascular network.
However, studies by Panoutsakopoulus et al.
and Oliveira et al.
uncovered the clonal neoplastic nature of aneurysmal bone cyst.
Primary cause has been regarded arteriovenous fistula within bone.
The lesion may arise de novo or may arise secondarily within a pre-existing bone tumor, because the abnormal bone causes changes in hemodynamics.
A giant cell tumor is the most common cause, occurring in 19% to 39% of cases.
Histologically, they are classified in two variants.
- The classic (or standard) form (95%) has blood filled clefts among bony trabeculae. Osteoid tissue is found in stromal matrix.
- The solid form (5%) shows fibroblastic proliferation, osteoid production and degenerated calcifying fibromyxoid elements.
According to Buraczewski and Dabska, the development of the aneurysmal bone cyst follows three stages.
|Initial phase (I)||Osteolysis without peculiar findings|
|Growth phase (II)|
|Stabilization phase (III)||Fully developed radiological pattern|
They can also be associated with a TRE17/USP6 translocation.
Aneurysmal bone cysts may be intraosseous, staying inside of the bone marrow.
Or they may be extraosseous, developing on the surface of the bone, and extending into the marrow.
A radiograph will reveal a soap bubble appearance.
On a radiograph, well-defined, expansile, lytic lesion is observed.
Expansion of cortex gives the lesion a balloon-like appearance.
Larger lesions may appear septated
Following conditions are excluded before diagnosis can be confirmed:
- Unicameral bone cyst
- Giant cell tumor
- Telangiectatic osteosarcoma
- Secondary aneurysmal bone cyst
Curettage is performed on some patients, and is sufficient for inactive lesions.
The recurrence rate with curettage is significant in active lesions, and marginal resection has been advised.
Recurrence rate of solid form of tumour is lower than classic form.
It is common in age group of 10–30 years.
It is second most common tumor of spine and most common benign tumor of pelvis in pediatric population.
Incidence is slightly more in males than females (1.3:1).
Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Aneurysmal bone cyst.