First-rib exostosis bursa

Imaging of osteochondroma: variants and complications with radiologic-pathologic correlation

Osteochondroma represents the most common bone tumor and is a developmental lesion rather than a true neoplasm. It constitutes 20%-50% of all benign bone tumors and 10%-15% of all bone tumors. Its radiologic features are often pathognomonic and identically reflect its pathologic appearance. Osteochondromas are composed of cortical and medullary bone with an overlying hyaline cartilage cap and must demonstrate continuity with the underlying parent bone cortex and medullary canal. Osteochondromas may be solitary or multiple, the latter being associated with the autosomal dominant syndrome, hereditary multiple exostoses (HME). Complications associated with osteochondromas are more frequent with HME and include deformity (cosmetic and osseous), fracture, vascular compromise, neurologic sequelae, overlying bursa formation, and malignant transformation. Malignant transformation is seen in 1% of solitary osteochondromas and in 3%-5% of patients with HME. Continued lesion growth and a hyaline cartilage cap greater than 1.5 cm in thickness, after skeletal maturity, suggest malignant transformation. Variants of osteochondroma include subungual exostosis, dysplasia epiphysealis hemimelica, turret and traction exostoses, bizarre parosteal osteochondromatous proliferation, and florid reactive periostitis. Recognition of the radiologic spectrum of appearances of osteochondroma and its variants usually allows prospective diagnosis and differentiation of the numerous potential complications, thus helping guide therapy and improving patient management.

Large bursa formation associated with osteochondroma of the scapula: a case report and review of the literature

Bursitis or large bursa formation associated with osteochondroma has rarely been reported. A 33-year-old male presented with upper back pain, a rapidly developing mass beside the lateral border of his right scapula and snapping elicited by movement of the scapula. Plain radiograms and CT revealed osteochondroma on the ventral surface of the scapula without any unmineralized component and a huge cystic lesion around the osteochondroma. Aspiration of the cystic lesion showed the presence of sero-sanguineous fluid. MRI following the aspiration showed a thin cartilaginous cap with distinct outer margin and no soft tissue mass around the cap. Pathological examinations confirmed the diagnosis of osteochondroma with the large bursa formation. Clinical examination 19 months postoperatively showed an uneventful clinical course.