The nutritional sources and limits of intraocular retinoblastoma growth.

The influence of the very limited potential for an increase of blood supply to the inner eye on the growth of intraocular retinoblastoma are listed, demonstrated, and discussed. It is typical for the most malignant retinoblastomas to present with the most massive ischemia and necrosis. The limited possibilities for vascular enlargement and neovascularization lead to cuff-like perivascular survival of neoplastic cells with necrosis in the interspaces. Indirect supply from retinal and ciliary sources explain layer-like neoplastic growth on surface and base of tumors as well as separation of living neoplastic cells, attraction towards exit areas, cyst formation, and seeding. These processes may contribute to extraocular extension. Recognition of the limits of intraocular nutrition also is important for prognosis and therapy in cases of retinoblastoma.