Naeem Z. Ahmed, MD

We describe a case in which a patient received thrombolytic therapy after he presented with a clinical picture consistent with submassive pulmonary embolism (PE). Two months later, a malignant peripheral nerve sheath tumor was diagnosed, and the patient died with metastatic disease. The filling defect in the left main pulmonary artery originally interpreted as PE was in fact a tumor. This case describes an unusual presentation of a rare disease (malignant peripheral nerve sheath tumor) mimicking a submassive PE.