THE METASTATIC PATTERNS OF OSTEOSARCOMA

Summary.-The paper presents a detailed comparison of the anatomical distribution and frequency of clinically evident metastases in 152 cases of osteosarcoma, and autopsy findings in 43 cases. The behaviour of long bone tumours is contrasted with those arising elsewhere, which tend to metastasize less widely because of early death from effects of the primary tumour. In both clinical and autopsy series long bone tumours produced lung metastases (LM) in over 90 % of patients dying with metastases, but the terminal frequency of extra-pulmonary metastases (EPM) rises from a clinical level of 33 % to 83 % at autopsy. There was little difference between tumours of the major long bones in the frequency of either LM or EPM, but EPM from the humerus tended to be fewer and sited above the diaphragm and from the femur below it. EPM most often involved other bones, notably vertebrae and pelvis. Not more than 10 % of tumours invaded regional lymph nodes but terminally a quarter of the long bone tumours had metastasized to heart and abdomen. The infrequency of metastases in muscle was confirmed