[A case of pulmonary thrombosis associated with primary antiphospholipid syndrome].

A 23-year-old man was admitted because of an attack of chest pain and dry cough. Chest roentogenogram showed a solitary pulmonary nodule in the left upper lobe. Chest CT showed a nodule and a small pleural effusion on the same side. Pulmonary thrombosis was diagnosed by pulmonary Ventilation/perfusion scintigraphy and pulmonary arteriography. Deep vein thrombosis was not detected except in a distal pulmonary artery. The solitary nodule disappeared spontaneously without thrombolytic therapy. An anticardiolipin antibody (IgG) test was positive. Primary antiphospholipid syndrome was diagnosed, because of the absence of physical findings suggesting other collagen vascular diseases. Patients with antiphospholipid syndrome have a high frequency of pulmonary complications that include pulmonary hypertension and pulmonary embolism. Most of the patients with pulmonary embolism have deep vein thrombosis, and pulmonary vessel thrombosis as seen in the present case is a rare complication.