Case report: calcification within aneurysmal bone cyst.

Aneurysmal bone cyst (ABC) usually affects older children or young adults. The radiological appearance is of a purely osteolytic expansile metaphyseal lesion with thinned out cortex and internal septations. We present a case of ABC in a 5-year-old girl which showed internal calcification and was initially diagnosed as enchondroma. However, pathological examination revealed typical appearance of ABC with large area of dystrophic calcification.