Nonneoplastic lesions that simulate primary tumors of bone.

CONTEXT: The skeletal system may be affected by a variety of nonneoplastic lesions, which may potentially be confused with primary bone tumors on clinical, radiologic, and pathologic grounds. These conditions include fractures, infections, and reactive and degenerative processes, as well as an array of quasineoplastic entities, such as intramedullary cystic lesions like unicameral and aneurysmal bone cysts; fibro-osseous lesions, such as fibrous dysplasia; and exophytic entities, like osteochondromas.
OBJECTIVE: To review clinical, radiographic, and histologic features of nonneoplastic lesions of bone, discussing the difficulties in diagnosis and the differential diagnosis with primary neoplasms of bone. DATA SOURCES: The sources include the more relevant medical literature on the different subjects and case-derived material.
CONCLUSIONS: Because many nonneoplastic bone lesions may require biopsy or resection, the general surgical pathologist must be familiar with these lesions and be aware that review of hematoxylin-eosin slides is only one of the many steps in the diagnostic process, which also includes review of imaging studies and all available clinical information. Morphologic analysis disconnected from the clinical and radiographic context may lead to misinterpretation.