Retinal pigment epithelial (RPE) hyperplasia is common in retinal disease, whereas RPE neoplasia is rare. In tissue sections it can occasionally be difficult to distinguish between the two conditions on morphological features alone. In a retrospective case series that addressed this issue, features thought to favour a reactive hyperplasia of the RPE included a history of previous ocular disease in the affected eye, conspicuous elaboration of basement membrane, rarity of mitotic figures, and histological pattern.¹ These features are not absolutely discriminatory. For example in case reports of RPE adenocarcinomas basement membrane elaboration has been detected.^2,3 Likewise, no mitoses were observed by light microscopy in a lesion eventually determined to be neoplastic⁴ and there were no unique histological patterns that differentiated hyperplasia from neoplasia. To complicate the issue there is evidence that neoplasia can arise from sites of hyperplasia/inflammation⁵ and RPE hyperplastic lesions can assume tumorous proportions.⁶ Therefore, some tumours still have to be placed equivocally in spectrum between definite …