Periosteal schwannoma of femur. (a) Radiograph shows a translucent external indentation in the cortical metaphysis at left. (b) CT scan shows a lucent periosteal nodule producing a well-delimited depression in the subjacent cortex

Medium-power microscopic view of a schwannoma with more crowded spindle cell areas (Antoni A) and a looser central area (Antoni B)

Medium-power microscopic view. Suggestive palisading of the nuclei of the spindle cells, at left, and large congestive blood vessels with thick hyaline walls