Aneurysmal bone cyst arising from fibrous dysplasia of the frontal bone (2004:2b)

Abstract

We report an 18-year-old man who had fibrous dysplasia (FD) of the left frontal bone with the development of secondary aneurysmal bone cyst (ABC) formation over a 2-week period. A sequential CT and MRI study clearly depicted a dramatic "blow-out" aneurysmal bone cyst transformation in FD due to secondary ABC formation. Rapidly progressive enlargement of the ABC secondary to a pre-existing lesion can have an aggressive imaging appearance, which should be differentiated from sarcomatous transformation. To our knowledge, this is the first radiology case report that clearly documents the process of secondary ABC arising from FD.