On plain film X-ray, ABCs classically appear as eccentrically located radiolucent cystic lesions circumscribed by a thin layer of the cortical bone. Trabeculations within the lesion can impart a multi-locular appearance, which has been colloquially described as a “soap bubble appearance.”

Magnetic resonance imaging (MRI) can delineate “fluid-fluid levels,” which, in ABCs, represent the layering of blood of differing densities atop one another. MRI can reveal also internal septations, peri-lesional extension, and edema.

The signs described are not pathognomonic for ABC because other lesions such as unicameral osseous cysts, giant cell tumors, osteoblastoma and telangiectatic osteosarcoma may show these characteristics.