Abstract
A retinal tumor in an 8-month-old boy clinically resembled a retinoblastoma. Light microscopic and ultrastructural examination revealed a hemangioblastoma (von Hippel's disease). It was mainly composed of large, light, lipid-containing cells (so-called stroma cells) lying between numerous vessels, which ultra-structurally were seen to be surrounded by several layers of pericytes separated by abundant basement membrane material. The origin of the stromal cells is discussed in particular. Ultrastructural examination of this tumor has not previously been performed in such an early case, but 2 adult cases have been recorded. Based on their findings the authors favor a vascular origin but conclude that the derivation of the stroma cell is still unresolved.