A 62-year-old man was referred to our clinic with a 4- to 6-week history of dyspnea and an abnormal finding on a chest radiograph. He had been in his usual state of health until 6 to 8 weeks previously, when he developed a low-grade fever and arthralgias. He denied having any cough or chest pain. Early in the course of his illness, he had lost six pounds, but by the time he was seen in the clinic he had regained the weight and his symptoms had improved. In the clinic, his only complaints were fatigue and mild-to-moderate dyspnea on exertion.