Growth patterns of retinoblastoma. a. Two foci of domeshaped retinoblastoma. Feeder vessels that dip into the mass and drainer vessels that emerge from the lesion’s periphery. b. Exophytic retinoblastoma that has grown under the retina producing exudative retinal detachment. c. Endophytic retinoblastoma that has grown into the vitreous cavity. The endophytic mass is characterized by the absence of visibility of retinal vessels. d. Diffuse infiltrating retinoblastoma that presents as an ill-defined whitish infiltration of the retina.