Unicentric Castleman's disease in the orbit: A case report.

A 53-year-old man presented with a palpable mass on the left lower eyelid and occasional diplopia. Under suspicion of orbital lymphoma, an excisional biopsy was performed, and histopathology revealed Castleman's disease. Castleman's disease is a rare disorder of the lymphoid system, and only a few cases of Castleman's disease in the orbit have been reported.