A 20-year-old man with rapid refractory pulmonary infiltrates, fever, and chill was admitted to our hospital. Microscopic examination showed focal necrosis of the lung tissue, arterial thromboembolism, and alveolar hemorrhage. He tested positive for anticardiolipin IgG antibodies. Because of the absence of underlying diseases, the possibility of secondary antiphospholipid antibody syndrome was excluded. Follow-up chest CT after 2 years revealed pulmonary arterial aneurysms with diffuse ground-glass opacities. The aneurysms were occluded by coil embolization.