The final chapter contains a discussion of the osseous lesions that are most apt to be confused with primary neoplasms of bone clinically and roentgenologically. FEATURES: The diagnostic aspects of bone tumors, which include their roentgenographic features and their gross path ologic characteristics as well as their histopathology are emphasized. It has become firmly established that the pathologist responsible for the definitive diagnosis of osseous lesions must consider especially these three major characteristics. Accordingly the text is liberally illustrated with photomicrographs and pictures of roent genograms and gross specimens. The principles of treatment for each tumor type are presented and the prognosis of each type of tumor is discussed. The clinical aspects of most bone tumors are relative ly nonspecific, so the discussion of the symptoms and findings at physical examination have been dealt with relatively briefly. The skeletal localization, incidence and age and sex distribution are detailed in the case of each tumor type. Bibliographic references have been limited to a few of the most important for each type of tumor. The au thor has also attempted to include significant references that present contrasting opinions on important aspects of these tumors.