title: The relationship between tumor cell differentiation and age at diagnosis in retinoblastoma.
abstract: OBJECTIVE
  To determine the relationship between tumor cell differentiation and age at diagnosis in retinoblastoma.
  
  
  METHODS
  Medical records of 170 patients with retinoblastoma treated by enucleation were reviewed retrospectively. Age at diagnosis and histopathological features were analyzed.
  
  
  RESULTS
  Well-differentiated tumors presented earlier than poorly differentiated tumors. The frequency of presentation was highest in the first year of age for well-differentiated tumors and in the third year of age for poorly differentiated tumors (P < .0001). Bilateral well-differentiated tumors presented earlier than bilateral poorly differentiated tumors. Similarly, unilateral well-differentiated tumors presented earlier than unilateral poorly differentiated tumors.
  
  
  CONCLUSIONS
  Differentiated tumors present earlier than poorly differentiated tumors, irrespective of laterality in retinoblastoma.
authors.affiliation: SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Jagadeesan
authors.initials: J
authors.lastname: Madhavan
authors.forename: Anuradha
authors.initials: A
authors.lastname: Ganesh
authors.forename: Joseph
authors.initials: J
authors.lastname: Roy
authors.forename: Jyotirmay
authors.initials: J
authors.lastname: Biswas
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Kumaramanickavel
mesh_terms: D017677:Age Distribution; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D015353:Eye Enucleation; D006801:Humans; D007223:Infant; D019572:Retinal Neoplasms / Q000473:pathology*; D012175:Retinoblastoma / Q000473:pathology*; D012189:Retrospective Studies