Pulmonary arterial sarcoma with a wide range of endovascular intima invasion microscopically.

A 69-year-old man underwent right middle and lower lobectomy for suspected lung cancer (cT3N1M0). The final pathological diagnosis was pulmonary artery sarcoma (PAS). The stump was positive despite having a sufficient surgical margin. After 11 months, we performed completion pneumonectomy and pulmonary artery (PA) resection and replacement under extracorporeal circulation for local recurrence. Although the PA was macroscopically intact, the frozen pathological diagnosis was positive three times. Since PAS extends microscopically through the intima of the PA, it is difficult to determine the extent of resection on imaging. We consider confirmation by a frozen pathological diagnosis to be essential.