CLINICOPATHOLOGICAL CORRELATION OF INTRARETINAL MICROVASCULAR ABNORMALITIES

Purpose: To define the cross-sectional morphology of intraretinal micr ovascular abnormalities, which previously have been described only in terms of trypsin digestion. Material/Methods: Fourteen vascular lesion s of five patients with diabetic retinopathy were identified on fundus photographs and/or fluorescein angiograms and classified as intrareti nal microvascular abnormalities. Eyes of these patients were obtained after the patients' deaths. The period between the time at which the p hotographs were taken and that at which enucleation was performed was 3-20 months. The duration of autolysis before fixation was 5 hours or less. The embedded tissue was evaluated by light and electron microsco py, and these findings were correlated with the clinical appearance, R esults: The lesions consisted of multiple, closely spaced, thin-walled vascular lumina with a caliber of 20-70 mu m. They were located in th e inner retina and surrounded by a wide cuff containing randomly orien ted collagen fibers. Endothelial cell nuclei were numerous. Pericyte d egeneration and multiplication of the endothelial and pericyte basemen t membrane had occurred. Endothelial junctions were short, and gaping of junctions was not seen. However, occasional fenestrations were pres ent. Conclusion: The cross-sectional morphology of intraretinal microv ascular abnormalities is consistent with vascular pathology typical fo r intraretinal diabetic microangiopathy, but also includes features us ually seen in new vessels. This supports the concept that intraretinal microvascular abnormalities have the particular potential for neovasc ularization.