Identify the imaging appearance of giant cell tumor, aneu-rismal bone cyst, simple bone cyst and subchondral bone cyst.

Recognize the relationships between these lesions.

Recognize how the radiologie images reflect the underlying patho-physiology.

Giant cell tumor is a common benign lesion that is most common in long bone, originating in the metaphysis and extending to the end of the bone.

Giant cell tumor is rare in children (2% of cases).

Aneurysmal bone cyst is the resuit of a hemorrhagic pathophysiology and may be primary or secondary.

Simple bone cysts are typically central, metaphyseal and occur most frequently in children.

Subchondral degenerative cysts are common, typically juxtaarticular and often not “cystic”.

This session is a review of these relatively common lesions, emphasizing radiographie-pathologie corrélation, and how the radiographs and imaging studies reflect the underlying pathophysiology. More importantly, this session explains how these lesions do and do not interrelate, specifically addressing the “fact and fiction” associated with the diagnosis of aneurysmal bone cyst (ABC) and the conflicting views of this diagnosis.