Primary choriocarcinoma of the pulmonary artery mimicking pulmonary embolism.

Due to their rarity, primary tumours of the pulmonary arteries are often incorrectly diagnosed as more common diseases such as pulmonary thromboembolism and are seldom diagnosed during a patient's lifetime. Surgery or potentially curative chemotherapy may therefore be withheld. We report a patient with a primary choriocarcinoma of the left pulmonary artery, which was first suspected on a CT scan. The neoplastic nature of the obstruction of the pulmonary arteries was confirmed by positron emission tomography.