The images show a partially ossified circumscribed mass within the right carotid sheath, surrounding the right CCA bifurcation.
Extraskeletal osteosarcomas are rare and present diagnostic difficulties.
They occur in older individuals. In this case, the closest differential diagnosis would be myositis ossificans. No osteosarcoma has been reported at this site in the English literature as yet. Resnick D. Diagnosis of Bone and Joint Disorders.