Abstract
Abstract: :
Purpose:Given the common genetic origin of combined corneal stromal dystrophy (SD)with that of granular and lattice SD (BIGH3 gene on chromosome 5q31), one would expect to see a more variable clinical presentation of this entity. However, previously published studies on the histopathologic appearance of combined SD reported that these cases present clinically as granular SD. The aim of this study is to determine the frequency of combined SD and whether combined SD may present clinically as either granular or lattice dystrophy. Methods:Fourteen cases, from 1993 to 2001, with previous histopathologic diagnosis of corneal SD were retrieved from The Henry C. Witelson Eye Pathology Laboratory. Cases were examined with H&E and periodic acid-Schiff. Specimens previously diagnosed as lattice SD had one slide stained with Congo Red (CR) and were analyzed with polarized light. For this study, Masson’s Trichrome (MT) stain was requested for such cases. Cases previously diagnosed as granular SD, had one slide stained with MT. CR was added for this study. If a diagnosis of combined SD had been previously assigned, 1 slide each of CR and MT was assessed. New histopathologic diagnoses were assigned where appropriate, and comparisons were made with the original histopathologic and clinical diagnoses. Results:Fourteen cases diagnosed histopathologically as corneal SD were retrieved: 2 were granular, 9 lattice, and 3 combined. The original histopathologic diagnosis changed in 3 lattice cases upon reanalysis to 3 combined SD, giving a final histopathologic diagnosis of 2 granular, 6 lattice, and 6 combined. Of the 6 combined SD cases, 3 had been clinically diagnosed as lattice and 3 as granular. Histopathologically, combined SD presented with 2 distinct deposit patterns: granular deposits in the subepithelium with lattice deposits in the stroma as well as both granular and lattice deposits present in both subepithelium and stroma simultaneously. Conclusion:Combined stromal dystrophy can present in a variety of phenotypic manners both clinically and histopathologically. This finding may be explained by the common genetic defect found in lattice and granular dystrophies. Therefore, when evaluating corneal buttons with a clinical diagnosis of lattice or granular corneal dystrophy, it should be kept in mind that combined SD may be more common than previously reported.
Keywords: 374 cornea: stroma and keratocytes • 354 clinical (human) or epidemiologic studies: prevalence/incidence • 507 pathology: human