Pulmonary tumor embolism: a critical review of clinical, imaging, and hemodynamic features.

Pulmonary tumor embolism is a common finding at autopsy but is generally perceived as a difficult diagnosis to make ante mortem. After a retrospective review of 164 reported cases of pulmonary tumor embolism, we identified a typical profile of clinical, laboratory, and imaging features that may permit confident clinical diagnosis in most patients with this condition. The clinical features include a documented or suspected underlying malignancy, acute to subacute onset of dyspnea, and signs of cor pulmonale. Supportive laboratory features are hypoxemia or increased alveolar-arterial oxygen gradient, and invasive or noninvasive evidence of pulmonary artery hypertension. Typical imaging findings are normal chest radiographs; multiple, subsegmental, peripheral perfusion defects on ventilation-perfusion lung scans; and delayed filling with or without subsegmental filling defects but without a thrombus on pulmonary angiogram. Radiolabeled monoclonal antibody imaging and pulmonary microvascular cytology sampling techniques are promising diagnostic tests for early diagnosis of pulmonary tumor embolism.