Tumours of the retinal pigment epithelium

Under normal circumstances there is little, if any, turnover of the pigment epithelium of the human retina, and this absence of opportunity for aberrant genetic mutations to occur may in part account for the rarity of neoplasia in this tissue. Moreover, in those rare instances where tumours have developed, they have not infrequently been preceded by a hyperplastic proliferation associated with chronic choroido-retinitis. To what extent such neoplasms can ever be regarded as malignant has been the subject of some debate, and Fair (I958) concluded that it was perhaps best to leave the question open until more cases had been presented for study. Over a space of 20 years three such tumours have been diagnosed in the Department of Pathology at the Institute of Ophthalmology, one of them having been previously reported by Greer (I952). It is the purpose of this present report to describe the pathology of the remaining two, as well as to comment on the prognostic implications of the histological findings in this type of neoplasm.