We report a case of diffuse retinoblastoma in a 6 years old boy. The diagnosis should be suspected in front of the very evocative clinical picture itself. The aspect of the tyndall phenomenon, and of the convex pseudo-hypopyon, with iris pearls and nodules, together with a peripheral, imprecisely limited, retinal mass, non calcified on ultrasonographic examination, are typical. Aqueous paracentesis shows increased levels of Lactic Dehydrogenase (LDH), but most of all the cytologic examination confirms the diagnosis. The only treatment is enucleation. The clinical picture which may simulate uveitis, especially as this particular type of retinoblastoma has a late onset.