Retinocytoma is often clinically indistinguishable from retinoblastoma. In Chapter 11, the histologic features that distinguish retinocytoma from retinoblastoma are summarized (see Fig 11-48). The developmental biology of retinocytoma is controversial. Some authorities assert that retinocytoma is a completely differentiated form of retinoblastoma—analogous to ganglioneuroma, the differentiated form of neuroblastoma. Others contend that retinocytoma is a benign counterpart of retinoblastoma in which biallelic RB1 mutations are present, but further genetic or genomic changes needed to promote tumorigenesis are absent. Though histologically benign, retinocytoma carries the same genetic implications as retinoblastoma. A child harboring a retinoblastoma in one eye and a retinocytoma in the other should be considered to have the same risk of transmitting an RB1 mutation to future offspring as children with bilateral retinoblastoma.
Singh AD, Santos MM, Shields CL, Shields JA, Eagle RC Jr. Observations on 17 patients with retinocytoma. Arch Ophthalmol. 2000;118(2):199–205.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.