Bone tumors, both benign and malignant, have predilection for specific bones and certain locations within a specific bone. Table 1.3 shows the predilection sites of certain tumors within the skeleton. For example, for an osteolytic intracortical lesion at the anterior tibia, the most probable diagnosis would be osteofibrous dysplasia or adamantinoma. The location of a lesion within a specific bone can be specified along the longitudinal axis (i.e., epiphysis, metaphysis, and diaphysis) and the transverse plane (i.e., central intramedullary, eccentric intramedullary, cortical, juxtacortical) (Fig. 1.1). For example, a simple bone cyst is typically a central intramedullary lesion in the metaphysis of a long bone, with the most common site being the proximal humerus (Fig. 1.2a). Chondroblastomas are characterized by its intramedullary epiphyseal location in a long bone (Fig. 1.2b). Nonossifying fibroma appears as cortical lesions of the metaphysis of a long bone (Fig. 1.2c). Parosteal osteosarcoma is an example of a juxtacortical location of lesion, and has a predilection for the posterior aspect of the distal femur (Fig. 1.2d). Recognizing these site predilections of different bone tumors will aid in the differential diagnoses of bone tumors. Table 1.4 shows the predilection sites in summary.