Clinical and histopathologic classification of retinal dysplasia

Retinal dysplasia was found in 2.1% of eyes (22 eyes) accessioned by the Yale Eye Pathology Laboratory between 1965 and 1971. In these eyes it was seen as an isolated defect or it occurred together with other systemic congenital abnormalities. In the group with systemic abnormalities, the changes were usually focal. When changes were limited to the eye (the isolated group), persistent hyperplastic primary vitreous was seen in the majority of eyes and the dysplasia was more extensive and diffuse. Histopathologically, four general types of rosettes were seen: (1) Three-layer rosettes were seen which had the appearance of mature retina which had been secondarily thrown into folds. (2) Two-layer rosettes were seen in which the innermost layer resembled a photoreceptor cell layer with external limiting membrane and a relatively large lumen usually containing several undifferentiated cells. Surrounding this was a more peripheral layer of bipolar-like cells or poorly differentiated cells. (3) One-layer rosettes were seen with a single layer of moderately well-differentiated neural cells, usually several cells in thickness, having an external limiting membrane-like structure and surrounding a lumen. Within the lumen larger undifferentiated cells were usually observed. (4) Primitive unilayer rosettes were seen in which a single layer of undifferentiated retinal cells surrounded a lumen or were arranged in a circle with a tangle of fibrils seen centrally. No correlation could be made between the occurrence and severity of systemic congenital abnormalities and the extent of the retinal dysplasia. The only significant correlation between the clinical classification and histologic findings was with regard to the primitive unilayer rosette, which was seen in the group with isolated retinal dysplasia.