Weekly Case

Title : Case 617

Age / Sex : 15 / F

Chief complaint : Right upper arm pain and swelling (3 weeks ago)

What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : 
Yoo Hye Jin, Seoul National University Hospital






X-ray: A broad-based surface soft-tissue mass in the diaphysis of the right midshaft of humerus involving the lateral cortex with perpendicular or sunburst pattern periosteal reaction.


MRI: Periosteal soft tissue mass with internal calcification in the diaphysis of the right midshaft of humerus involving the lateral cortex.

- appears hyperintense on T2 sequence, which represents its chondroid matrix.

- with periosteal hypointense portion on both T1 and T2 sequences, suggesting periosteal bone formation

- with heterogeneous contrast enhancement.

- no cortical or intramedullary bone involvement.


Differential Diagnosis:

Central osteosarcoma, Parosteal osteosarcoma



It is the second most common type of surface osteosarcoma after parosteal osteosarcoma and accounts for 1.5% of all osteosarcoma cases. It affects a slightly older age group (10-20 years).

Periosteal osteosarcoma arises from the inner layer of periosteum (parosteal osteosarcoma arises from outer layer) and contain large amount of cartilaginous matrix. Histologic grade of this tumor is higher than parosteal osteosarcoma and lower than conventional osteosarcomas, so it is considered as an intermediate grade osteosarcoma (grade 2). It predominantly contains chondroid matrix. It usually arises from cortex, being attached to underlying cortex at origin, but intramedullary extension is rare.

A central osteosarcoma is a central destructive lesion with varying amounts of osteoid matrix, is radiographically discernable. The tumor is aggressive with poorly defined matrix and damaged cortex. In parosteal osteosarcoma, a radiolucent zone between tumor and the bone of origin indicates a void between tumor mass, outgrowing its pedicle and cortex of the normal bone. The medullary cavity is violated and daughter mass is frequently observed. There is a mushrooming mass attached with a thick pedicle, which circumvents the shaft of origin and often invades the medullary cavity.

A periosteal osteosarcoma is of intermediate grade with prognosis being better than conventional osteosarcoma, but not as good as parosteal osteosarcoma (which is usually low grade).



Radiology 2004; 233 (1): 129-038. Imaging of Periosteal Osteosarcoma: Radiologic-Pathologic Comparison

Int J Clin Exp Med. 2015; 8(1): 37–44. Periosteal osteosarcoma: a review of clinical evidence

Correct Answer
Total applicants 37 Correct answers 20
Name Institution
김기욱 국군대전병원, 전문의
권소이 전문의
이혜란 전문의
윤유성 순천향대 부천병원, 전문의
장성원 중앙보훈병원, 전공의
박종원 전문의
권영호 경희의료원, 전문의
강지희 서울대학교병원, 전문의
이승은 전문의
김지은 서울대학교병원, 전문의
이진영 전문의
한진우 전공의
최형인 국군의무학교, 전문의
김동수 전공의
송윤아 전문의
김창현 전문의
최희석 전병원, 전문의
정보미 전문의
김보람 전문의
임윤진 전공의