MSK Case 1: Juxtacortical chondroma
Imaging Sciences URMC 2008
Publication Date: 2009-06-04
A 10-year-old female presents with a five year history of a slowly enlarging painless lesion on her left index finger of about 2cm. She is unable to make a strong fist due to interference with the middle finger.
Imaging Findings: Plain films (Figs. 1A & B) reveal a well-circumscribed, faintly calcified lesion with epicenter in the juxtacortical region of the proximal phalanx of the index finger. There is sclerosis in the abutting diaphysis portion of the proximal phalanx. There is saucerization of the adjoining cortex and no significant periosteal reaction. No communication with the marrow space is present. MRI was not performed. The lesion was subsequently excised.
Bone, cartilage and soft tissue were noted in left index finger excision specimen. Pathologic specimen of the lesion was initially erroneously diagnosed as osteochondroma but subsequent review of and correlation with plain radiographs determined the correct diagnosis to be a juxtacortical chondroma.
Differential Diagnosis based on radiographic appearance include juxtacortical chondroma and bizarre parosteal osteochondromatous proliferation (BPOP).
Juxtacortical chondroma (or periosteal chondroma) is a benign cartilaginous lesion with epicenter at the surface or just underneath the periosteum. It most commonly occurs in the metaphyseal region of long tubular bones, frequently at sites of tendon or ligament insertions. Characteristic findings include erosion of the cortex with sclerotic inner border. Calcifications are common and a solid “buttress” of periosteal new bone may be seen. On CT the lesion can be demonstrated to be separate from the medullary cavity, which distinguishes juxtacortical chondroma from osteochondroma. MRI demonstrates cartilaginous tissue in a well-defined lobular lesion best appreciated on T2 weighted sequence.
Juxtacortical chondromas are relatively rare and account for approximately 2.2% of benign bone tumors. They may occur at any age but have a peak occurrence in the second through fourth decades. There is slight predilection for males. Clinical presentations may vary. The lesions are generally painless although as the lesion enlarges pain may occur.
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