[Primary malignant peripheral nerve sheath tumor of the lung; report of a case].

We report a patient with primary malignant peripheral nerve sheath tumor (MPNST) of the lung. A 84-year-old man was referred to our hospital because of an abnormal shadow on chest X-ray. The computed tomography( CT) of the chest revealed a 6 cm tumor close to the posterior chest wall in the left thorax. He was followed-up because a benign tumor from posterior mediastinum was suspected. But the CT after 17 months showed the tumor enlargement. We performed complete resection under video-assisted thoracic surgery. It arose from the left lower lobe and was diagnosed as primary MPNST of the lung by immuno-histopathological examination. MPNSTs have a poor prognosis with tendency to recur. Although there is no sign of recurrence a year after surgery, we should follow-up carefully.