effusion may obscure a mass on both chest x-ray and chest CT scan Malignant pericardial effusions are most often associated with leukemias and lymphomas For general diagnosis and management of pulmonary and pericardial effusions see Chapters 86 Cardiac Emergencies and 99 Pulmonary Emergencies Askin tumor or metastatic sarcomas may present as a chest wall mass with or without pain More commonly, it presents with respiratory symptoms from an effusion