Retinoblastoma

A 2-year-old child is brought to the pediatric ophthalmology clinic after parents notice a white pupillary reflex (leukocoria) on flash photographs and new-onset convergent strabismus of the left eye. On examination, the affected pupil shows leukocoria with loss of the red reflex. Family history is significant for a maternal uncle who had one eye enucleated in childhood. Contrast-enhanced orbital CT is performed. The structure marked **C** in the diagram shows a hyperdense intraocular mass arising from the retina with chunky intralesional calcifications. Which of the following best explains why the presence of intraocular calcifications in this mass is diagnostically significant in a child under 3 years?