A 23-year-old woman was admitted to our hospital because of an intrapulmonary mass that had been observed for 7 years. Chest computed tomography revealed a 3.5-cm well-defined mass with enhancement in the left lower lobe. During the 7 years of observation, she had been asymptomatic and the tumor size was unchanged. She underwent surgical resection for diagnosis and treatment. Histological examination revealed Castleman's disease of the hyaline vascular type. We present this rare case of solitary Castleman's disease arising from an intrapulmonary lymph node.