Unilateral retinoblastoma in an adult: report of a case and review of the literature.

PURPOSE: The authors report the clinical, cytologic, and histopathologic findings of a unilateral retinoblastoma occurring in a 26-year-old woman. This tumor usually affects young children; the mean age at the time of diagnosis usually ranges from 10 to 25 months.
METHODS: Histopathologic examination of the enucleated right eye included using standard techniques, as well as immunohistochemical stains of formalin-fixed, paraffin-embedded tissues.
RESULTS: Histologic examination of sections of the eye showed a retinal tumor that was centered in the equatorial region and had the typical features of a poorly differentiated retinoblastoma. Focal choroidal invasion and seeding of the anterior and posterior chambers were observed. Immunoreactivity of the tumor cells for neuron-specific enolase confirmed that the tumor is a neuronal neoplasm consistent with retinoblastoma.
CONCLUSION: Retinoblastoma occurring in adults is a rare finding. In most large series of retinoblastomas, no adults are included. Only eight patients 20 years of age or older with retinoblastomas have been documented previously. In the current case, the patient had no evidence of orbital recurrence or metastasis 6 years after enucleation of the eye. It may be important for clinicians to consider this diagnosis when confronted with a retinal mass of unknown etiology in adults.