An insight into corneal button histopathology in dystrophies following keratoplasty: A prospective study

Abstract

B.N. Nandeesh, Usha Kini, Rekha Gyanchand, Anil Felix Fonseca

Background: The prognosis and outcome of a tissue transplant is dependent on its pathology and though, penetrating keratoplasty (PKP) is the most successful tissue transplant, most of its studies are genetic/ clinical based. This histopathology study on corneal dystrophies is aimed at correlating clinicopathology with graft outcome in an attempt to understand the pathology better. Materials and Methods: Corneal buttons from all age groups where PKP was performed for dystrophy/degeneration were prospectively selected over 3½ years by convenient sampling. Corneal buttons of keratoconus and bullous keratopathy (aphakic/ psuedophakic) following PKP were also studied, though they are neither specific dystrophy/degeneration and showed non-specific stromal changes. Results: One hundred and ten corneal buttons (40.3%) with dystrophy (n = 44) and degeneration (n = 66) from 273 cases of PKPs were studied histopathologically. 90% of dystrophies and 66% of degenerations showed a very good clinicopathologic correlation. Macular, Lattice and Avellino’s dystrophies among dystrophies and Salzmann’s nodular degeneration showed specific stromal deposits making them easily diagnosable at histopathology, whereas the rest showed non-specific stromal changes mandating correlation with clinical findings. Seven regraft corneas showed stromal fibrosis making identification of primary dystrophy impossible. However, transmural vascularization and lymphocytic stromal infiltrate were prominently noted in failed grafts though their numbers were few. Conclusion: This histopathologic study characterizes classic features of macular, Avellino’s, lattice corneal dystrophies and Salzmann’s degeneration for their microscopic diagnosis, while the rest showed non-specific changes. Stromal edema was prominently noted in degenerations than in dystrophies. Degree of stromal vascularization and type of cellular infiltrate need attention in regrafts.