Castleman's disease along the left tracheobronchial tree with a difficult preoperative diagnosis

A 39-year-old man was referred to our hospital because of an asymptomatic middle mediastinal tumor. A preliminary histological diagnosis of the tumor by bronchoscopy was difficult to obtain because the tumor was located along the left tracheobronchial tree, which is difficult to approach. The tumor was resected through a right anteroaxillary thoracotomy without any major complications, and histopathological examination revealed that the lesion was Castleman's disease, hyaline-vascular type. Radiological findings of the lesion were typical; however, the rarity of the tumor made the imaging diagnosis difficult. If a lesion is located along the tracheobronchial tree, Castleman's disease should be considered in the differential diagnosis.