An adolescent male patient presented with pleural effusion of undetermined etiology which was unresponsive to antituberculous therapy. He died suddenly a few months later and was found at autopsy to have suffered from acute catastrophic pulmonary occlusion, secondary to embolization from retroperitoneal chondrosarcoma which had invaded and occluded the pulmonary arteries via the inferior vena cava. The rarity of this phenomenon in children prompted this report.