Purpose
We hypothesize that there are cytologic characteristics of retinoblastoma that may be important for prognostication. Cellular anaplastic change is known to be a significant phenotypic expression of genetic instability and malignant transformation that can be readily recognized under a microscope. The objective of this study is to determine whether the degree of anaplasia correlates with routinely assessed histologic features and clinical outcomes in a series of retinoblastoma patients.
Methods
This retrospective study involved the review of demographic, clinical, and pathologic findings from 92 patients who underwent primary enucleation for retinoblastoma. Anaplasia was graded as none, mild, moderate, or severe; defined by increasing nuclear size, number of mitoses, nuclear hyperchromatism, pleomorphism and angularity. Pathologic and clinical data were compared using Kaplan-Meier estimates of event free survival and overall survival. The Fisher’s exact test was used to analyze the association between anaplasia grade and other histologic factors.
Results
The distribution of anaplasia grades was as follows: 15 mild (16%), 53 moderate (58%), and 24 severe (26%). Six tumors had retinoblastoma associated with retinocytoma; all retinocytoma components had no anaplasia. Increasing grade of anaplasia was associated with decreased overall survival (p=0.03). There was no statistically significant correlation between anaplasia and event free survival. Histopathologic factors statistically associated with anaplasia were level of differentiation (p<0.001), optic nerve invasion (p=0.005), and choroidal invasion (p=0.02).
Conclusions
Anaplasia grading may be a useful adjunct to standard histopathologic criteria in identifying high risk retinoblastoma patients who may need adjuvant therapy.
Keywords: 703 retinoblastoma •
744 tumors •
638 pathology: human