Flexner-Wintersteiner rosettes in microscopy is seen in: September 2009

Ans. C: Retinoblastoma Leukocoria (white pupillary reflex or cat's eye reflex) is the most common presenting sign of retinoblastoma, accounting for about 56.1% of cases. Strabismus, which occurs as a result of visual loss, is the second most common mode of presentation. Thus, funduscopic examination through a well-dilated pupil must be performed in all cases of childhood strabismus. Retinoblastoma can cause secondary changes in the eye, including glaucoma, retinal detachment, and inflammation secondary to tumor necrosis. Pseudouveitis, with a red eye and pain and associated hypopyon and hyphema, is a rare presentation. It is characteristic of an infiltrating type of retinoblastoma in which the tumor cells invade the retina diffusely without forming a discrete tumor mass. Orbital inflammation mimicking orbital cellulitis may occur in eyes with necrotic tumors and does not necessarily imply extraocular extension. Proptosis is a more common presenting symptom in most underdeveloped countries. Histologically, the growth consists chiefly of small round cells with large nuclei resembling the cells of the nuclear layers of the retina. Many of these cells stain poorly, showing that they are undergoing necrosis. Flexner-Wintersteiner rosettes like formation of cells resembling the rods and cones may be found.