Age / Sex : 52 / F

Periosteal chondroma (=Juxtacortical chondroma)

Discussion

Findings:

1) Radiograph

Calcification at posteroinferior aspect of humeral neck, with adjacent osteolytic bone change

2) MRI

 A well-defined, lobulated T2-high SI mass with arc-and-ring enhancement, centered at posterior cortex of humeral neck, with adjacent medullary bone erosion and periosteal reaction. 

Differential Diagnosis: periosteal chondrosarcoma 

Diagnosis: periosteal chondroma 

Discussion:

1) chondroid origin tumor, arising in the periosteal layer of tubular bones, and are sometimes termed juxtacortical

2) rare(<2%) of all chondroma

3) Location: metaphysis of humerus and femur (70%), phalanges(25%)

4) Imaging finding

• Radiograph: saucerization of adjacent cortex, sclerotic margination, dense periosteal reaction, matrix calcification (50%)


• MRI: iso or low T1 signal intensity / high T2 signal intensity, heterogeneous enhancement, generally at periphery of lesion. Intramedullary involvement (20%), intramedullary edema (20%)

References:

 Robinson et al.  AJR 2001;177:1183–1188

Liu et al.  Int J Clin Exp Med 2016;9(6):9908-9916