Aneurysmal Bone Cyst: Symptoms, Diagnosis and Treatment
Aneurysmal Bone Cyst is a tumor of bones characterized by the presence of a cavity with in bone that is filled with vascular tissue. It is usually seen between the age of 10 to 20 years. It is slightly more common in females.
Usual site of occurrence is at the ends of long bones such as the lower end of femur or thigh bone and the upper end of humerus. It can also involve the spine.
These cysts can be of three types
- Primary cysts that arise spontaneously from bone
- Secondary cysts that are associated with other lesions of bone such as Giant cell tumor, Fibrous Dysplasia, Osteosarcoma and Chondrosarcoma
- Traumatic cysts that develop at sites of previous bony injury
These cysts have a tendency to expand and the bone becomes blown up like a balloon.
As the bone becomes expanded and weak so the symptoms usually seen are pain, swelling and difficulty in movement of the involved extremity. A fracture of the weakened bone may also occur.
If the spine is involved then there may be pain along the nerves, sensory loss or even paralysis due to compression of the nerves.
Diagnosis of the aneurysmal bone cyst is made x rays. X ray picture is variable. Typically x rays show a eccentric expansion of the involved bone. A CT or MRI scan may also be required to accurately document the extent of the cyst and its spread in to surrounding tissues.
Diagnosis is confirmed by biopsy. Biopsy also helps to determine if the cyst is a primary or a secondary type. To establish if the cyst is primary or secondary many biopsy samples must be taken from the different sites in the cyst.
Treatment can be of two types
- Arterial Embolization
- Injection of calcitonin and methylprednisolone in to the cyst
- Curettage of the cyst
- En Bloc excision
In arterial embolization the artery supplying blood to the cyst is located and then a substance is injected to block this artery. This cuts off the blood supply to the cyst. This causes death of the cyst and eventually healing occurs. It is a new method and few patients have been treated by it.
Injections of calcitonin and methylprednisolone in to the cyst have been used in a few cases where surgery was very risky.
Medical treatment is avoided in patients with a fracture or neurological involvement.
During curettage a small window is made in the cyst wall and all its contents are removed with a spoon like instrument called a curet. The cyst is then filled with bone chips.
In en bloc excision the cyst is removed along with a margin of normal bone or tissue. The defect that remains is then reconstructed with a bone graft or a implant.
Secondary aneurysmal bone cysts are treated as the condition, with which they have been found to be associated after biopsy.
Frequently Asked Questions
Can the cyst recur after treatment?
Cyst recurrence can occur with in 1 to 2 years after treatment. Close monitoring is required during this period. Earlier the recurrence is detected the easier it is to treat.
Growth abnormalities can occur in children. They should be monitored till their growth is complete.
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This page was created on 22nd October 2010
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