juxtacortical osteogenic sarcoma

jux·ta·cor·ti·cal os·te·o·gen·ic sar·co·ma

a form of osteogenic sarcoma of relatively low malignancy, probably arising from the periosteum and initially involving cortical bone and adjacent connective tissue, which occurs in middle-aged as well as young adults and most commonly affects the lower part of the femoral shaft.
Synonym(s): periosteal sarcoma