Cytodiagnostic clues to primary retinoblastoma based on cytologic and histologic correlates of 39 enucleated eyes.

In 39 cases undergoing ocular enucleation, cytologic characteristics of primary intraocular retinoblastomas were examined in relation to histologic findings. Retinoblastoma cells occurred singly or in clusters within the associated necrotic debris. Calcific deposits were present in both cytologic and histologic specimens. Portions of capillaries with perivascular tumor infiltrates were identified as pseudorosettes. Wright rosettes were occasionally seen in poorly differentiated retinoblastomas. Flexner-Wintersteiner rosettes were uncommon; however, "mirror ball-like" clusters in cytologic materials correlated well with the rosettes and were a diagnostic clue. Cytomorphologically, the tumor cells could be divided into two types that reflected their histologic grading of differentiation. These findings are cytodiagnostic clues to the presence of retinoblastomas and can be helpful in the cytologic diagnosis.