Catheter-based interventions provide an important alternative to medical surgical management of massive central pulmonary thromboembolism. Because this option is increasingly being used, it is important to recognize that not all pulmonary thromboemboli are bland. The authors describe two cases in which tumor masqueraded as bland thromboembolism. Identification of tumor thromboembolism may help to alter future work-ups, provide useful prognostic information for a patient, and affect future treatment options.