Pulmonary metastases and bone sarcomas. Surgical removal of lesions appearing after adjuvant chemotherapy. Pulmonary metastasis is the leading cause of death in pediatric patients with bone tumors. Multiple thoracotomies for surgical removal of individual lesions are performed at many centers. To explore the efficacy of this procedure and establish guidelines for an appropriate choice of patients, the experience with 43 thoracotomies in 24 children was reviewed. The appearance of first metastasis later than one year after diagnosis, presence of fewer than five nodules, and completeness of surgical resection were favorable predictors of postthoractomy survival. Early or multiple metastases, unresectable disease, and hilar, nodal, or pleural lesions conferred an unfavorable prognosis. With careful patient selection, pulmonary metastecotomy is a safe procedure that has few operative or long-term complications. It must be emphasized that although surgical removal of pulmonary metastases prolongs survival with good quality of life, the majority of patients with bone sarcomas ultimately succumb to their disease after thoracotomy. Follow-up time of greater than eight years is necessary to adequately assess the effectiveness of pulmonary resection in eradicating all disease in these patients. 