Flexner-Wintersteiner rossette is seen in-

Harshmohan textbook of pathology 7th edition the microscopic structures of retinoblastoma characteristically arranged in rossettes. The rossettes are of 2 types 1. Flexner Wintersteiner rossettes characterised by small tumor cells arranged around a lumen with their nuclei away from the lumen. 2. Homer Wright rosettes- having radial arranarrangement of the tumor cells around the central neurofibrillar structure..