Photomicrographs of retinal hemangioblastoma. (A) The retinal hemangioblastoma was composed of classical foamy (tumor) cells admixed with small capillaries. Osseous tissues (asterisks) are adjacent to the retinal hemangioblastoma. (B) The hemangioblastoma shows high expression of vascular endothelial growth factor (VEGF). (C) Hypoxia-inducible transcription factor 1α (HIF-1α) is expressed in the retinal hemangioblastoma. (A, hematoxylin and eosin, original magnification, ×200; B and C, avidin-biotin complex immunohistochemistry, original magnification, ×200).