Differentiation in retinoblastoma and histopathological risk factors in Mexico.

PURPOSE To describe the relationship between retinoblastoma differentiation, histopathological risk factors, age at enucleation, laterality, and genetic type (hereditary or sporadic) in a series of enucleated eyes in a referral hospital. The criteria used in other studies to classify retinoblastoma differentiation are discussed. METHODS The authors retrospectively studied histopathological preparations of eyes with retinoblastoma treated with primary enucleation. Tumors were classified as well differentiated, undifferentiated, and moderately differentiated. Patient age at enucleation, laterality of disease, genetic form (hereditary or sporadic), and presence of histopathological risk factors (massive choroidal infiltration, postlaminar optic nerve invasion, tumor in optic nerve cut, scleral invasion, and involvement of orbital soft tissues) were analyzed. The chi-square test was used for categorical variables and analysis of variance for test mean differences. RESULTS Histopathological risk factors were present in 23 (36%) of 63 eyes. Moderately differentiated tumors occurred at advanced ages and were more frequently associated with histopathological risk factors. CONCLUSIONS A consensus is needed to establish the histopathological criteria of retinoblastoma differentiation. The value of rosettes as a marker of cell differentiation should be reviewed.[J Pediatr Ophthalmol Strabismus 2013;50(3):174-177.].