- It occurs mostly in children
- In the metaphysis of one of the long bones
- Occasionally in the small bones (adult carpus)
- It is not a tumour
- Heals spontaneously and seldom seen in adult
- It is discovered after pathological fracture or as an incidental finding on x-ray.
It begins as a spherical lesion but as it enlarges it tends to become oblong. It tends to lie centrally rather than grow eccentrically. The remaining cortex may appear expanded in all direction. The lining membrane consist of flimsy fibrous tissue and often containing giant cell. After pathological fracture the lesion often heals spontaneously.
Symptom less Unless a pathological fracture occurs.
Well demarcated radiolucent area in the metaphysis, often extended up to the metaphyseal plate. The cortex may be thinned and the bone expanded.
- Non ossifying fibroma
- Fibrous dysplasia
- Cartilage tumour
Asymptomatic lesion :
- Left alone.
- Advised to avoid injury.
Active Cyst : Sequential x-ray shows the cyst is abutting against the physeal plate.
- Injection Methyl prednisolone 80-160mg
- Autogenous bone marrow.
Cyst with pathological fracture :
- cavity cleaned by curettage and packed with bone chips. Care should be taken not to damage the epiphyseal plate.
- Prophylactic internal fixation can be done.
There is risk of cyst recurrence. More than one operation may be needed.