Surface aneurysmal bone cysts: a pictorial review.

The aim of this article is to present the imaging features of surface aneurysmal bone cysts (ABCs). Twenty-three surface ABCs were identified from of a series of 144 histologically proven ABCs treated in our unit over the past 20 years. The surface ABCs showed a high female preponderance with a predilection for the forearm bones, tibia and femur. With the use of radiographs in all cases and CT and MR imaging in 18 cases it was possible to subdivide the series into subperiosteal (11 cases), cortical (8 cases) and mixed (4 cases) categories. The imaging features distinguishing the various categories are illustrated and the differential diagnosis is discussed.