Benign epiphyseal tumour in children; M>F; most commonly in proximal tibia and distal femur. Usually painful. X-ray – radiolucent lesion with fine punctate calcifications oval osteolysis in epiphysis – some expansion and broadening of cortex – with a well defined surrounding margin of bone. Most in foot are in region of anterior calcaneus.
Often confused with unicameral or aneurysmal bone cysts.
Treatment – wide excision.