FIG 5. Histopathologic section from autopsy shows Ethibloc (purple staining material) together with recent thrombus filling a side branch of the right vertebral artery (RVA). The side branch is distended, with necrosis of the arterial wall (arrows). Osteoid (O) and loose fibrovascular tissue of the aneurysmal bone cyst is seen on both sides of the arterial branch. Sectioning artifact (SA) is also seen. (Block 28, C2 vertebra, level 352, Movat’s pentachrome stain, x20 original magnification.)