periosteal chondroma

Juxtacortical chondromas, also known as periosteal chondromas, are rare benign chondral tumors that arise from the periosteum of tubular bones. They are thought to account for ~2% of benign bone tumors.

Epidemiology

They tend to present around the 2 to 4 decades. There is a recognized male predilection .

Location

Typical sites include :

  • proximal humerus and distal femur (70%)
  • phalanges (25%)
  • tibia
  • radius
  • ulna

Radiographic features

Plain radiograph
  • may be seen as a saucerisation of the adjacent bony cortex with a sclerotic periosteal reaction
  • distinct soft tissue mass may be difficult to identify
  • matrix calcification may be seen in ~50% of cases; as with all chondroid lesions, this tends to be ring and arc
  • most lesions are <3 cm in size
MRI

Typically seen as a soft tissue lesion abutting the cortex and may better demonstrate evidence of pressure erosion of neighboring bone. Often has a lobulated configuration. Tends to lack associated medullary bone or soft tissue edema.

Signal characteristics include :

  • T1: typically iso to low signal relative to muscle 
  • T2/T2*: high signal but with low signal areas representing calcification
  • T1 C+ (Gd): heterogeneous and tends to show peripheral predominant contrast enhancement

Treatment and prognosis

They are benign lesions, however, may be similar in imaging and histopathologic appearance to juxtacortical chondrosarcomas. Local excision is often the treatment of choice. Once resected lesions usually do not recur.

Differential diagnosis

Imaging differential considerations include:

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