Benign tumors of bone include a wide diversity of lesions of various origins, with osseous and cartilaginous lesions being the most common. A number of tumor-Like lesions, including secondary aneurysmal bone cysts, unicameral bone cysts, and intraosseous gangLions are considered reactive, that is, nonneoplastic in nature. Some of these entities may have identical histological features and are separated largely on cLinical and radiological rounds (i.e., nonossifying fibroma and benign fibrous histiocytoma). Other lesions may have indistinguishable radiological characteristics but occur in different patient populations and exhibit distinct histomorphologic features (i.e., chondroblastoma and giant cell tumor of bone). Thus, correlation of the cLinical, radiological, and pathological features of the lesion is required to reach the correct diagnosis for any bone tumor.