Pulmonary dirofilariasis (PD), caused by Dirofilaria immitis (D. immitis), the dog heartworm, is not common in humans, though we recently encountered 4 cases. Chest X-ray images from annual health examinations showed a single spherical nodule in the inferior or middle portion of the right lung in each patient. None of the patients showed any clinical symptoms and had no contact with dogs. Hemat...
