A 53-year-old man with a 2-month history of left periorbital swelling was found to have a large solid intraconal mass on CT scan. Orbital ultrasound showed that the lesion had a cavernous pattern of internal reflectivity. Histopathology revealed hyaline-vascular type Castleman disease (CD). This article represents the first reported orbital ultrasound findings in CD. The findings of CT scan and ultrasound may be useful in the preoperative evaluation of orbital hyaline-vascular type CD.