Pleural and pulmonary metastases of a fibroblastic femoral osteosarcoma

The lung represents the predominant site for thoracic metastases of osteosarcoma. Pleural involvement occurs less frequently, while endobronchial, interstitial, endovascular, and parietal metastases are rare. We report the case of a 23-year-old male patient, with no history of toxic exposure, who sustained a fall onto his right lower limb during sports activity five months prior to hospitalization, resulting in persistent inflammatory pain localized to the right knee. One month before admission, the patient presented with respiratory symptoms characterized by stage I dyspnea according to the modified Medical Research Council (mMRC) scale, left-sided chest pain, and a dry cough, accompanied by a decline in general condition. Thoracic computed tomography revealed multiples pulmonary nodules with left pleural effusion. Magnetic resonance imaging of the right knee identified a locally advanced tumor involving the diaphyseal, metaphyseal, and epiphyseal regions. Histopathological examination of pleural biopsy specimens confirmed pleuropulmonary metastases originating from a femoral fibroblastic osteosarcoma.