Which tumor is classically described as having onion skin periosteal reaction on imaging?

Which tumor is classically described as having onion skin periosteal reaction on imaging?

• A. Ewing Sarcoma
• B. Osteosarcoma
• C. Chondrosarcoma
• D. Rhabdomyosarcoma

Answer: (A)

Onion-skin periosteal reaction is a laminated, layered new bone pattern produced when the periosteum is rapidly raised by an aggressive lesion. This radiographic appearance is most classically associated with Ewing sarcoma, a malignant small round blue cell tumor that typically affects children and adolescents and often involves the diaphysis of long bones. The rapid growth of Ewing leads to alternating layers of reactive and new bone, giving that characteristic onion-like look on X-rays. Clinically, Ewing can present with bone pain and sometimes systemic symptoms, which can mimic infection. Osteosarcoma, by contrast, more commonly shows a sunburst periosteal reaction with a Codman triangle and tends to arise in the metaphysis. Chondrosarcoma usually demonstrates chondroid matrix with ring-and-arc calcifications. Rhabdomyosarcoma is a soft-tissue tumor that may invade bone but does not characteristically produce the onion-skin reaction.

Onion-skin periosteal reaction is a laminated, layered new bone pattern produced when the periosteum is rapidly raised by an aggressive lesion. This radiographic appearance is most classically associated with Ewing sarcoma, a malignant small round blue cell tumor that typically affects children and adolescents and often involves the diaphysis of long bones. The rapid growth of Ewing leads to alternating layers of reactive and new bone, giving that characteristic onion-like look on X-rays. Clinically, Ewing can present with bone pain and sometimes systemic symptoms, which can mimic infection.

Osteosarcoma, by contrast, more commonly shows a sunburst periosteal reaction with a Codman triangle and tends to arise in the metaphysis. Chondrosarcoma usually demonstrates chondroid matrix with ring-and-arc calcifications. Rhabdomyosarcoma is a soft-tissue tumor that may invade bone but does not characteristically produce the onion-skin reaction.