Chondroma (periosteal)

 


Definition
Periosteal chondroma a chondroma that develops from periosteum or periosteal connective tissue.
 
Radiographic Appearance
Consists of small surface mass ( < 3 cm) & appears as radiolucent oval or oblong defect on periphery of underlying cortex;
The lesion is underlined by a thin, distinct cortical reaction,  has little or no calcification. (in contrast to chondrosarcoma), occassionally there is intralesional calcifications minimal periosteal reaction.
CT is used to demonstrate extent of cortical involvement and identify density of cartilage.
 
Pathology
Cartilaginous tumor that arises from surface of cortex deep to the periosteum, producing a broad based cartilaginous mass that may extend into soft tissues;
Often develops after adolescence (in contrast to osteochondroma)
Persists as mass of mature cartilage w/o calcification or ossification (in contrast to chondrosarcoma);
Tumor is does not infiltrate the adjacent soft tissue but may increase in size;
Over 50% of these tumors are found in lateral cortex of proximal humerus just proximal to insertion of deltoid muscle, other lesions are evenly dispersed thru out the long bones;
Clinical Manifestation, patients may complain of pain at tumor site; often can be palpated and is nontender, hard mass, fixed to bone.
 
Treatment:
Most of these lesions present in stage 2 & require en bloc marginal excision to prevent recurrence;
A wide excision including underlying cortex is treatment of choice, it is important to remove entire tumor without rupturing tumor capsule
The  risk of recurrence after bloc marginal excision is < 10%.
 
Image 1

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