Abstract:
To report a new corneal dystrophy in a patient with Alport’s syndrome.A 59–year–old female with longstanding diagnosis of Alport’s syndrome was seen by the Corneal Service at Walter Reed Army Medical Center for progressively decreasing vision. She had anterior lenticonus and cataract, and central corneal opacification with significant thinning and flattening bilaterally. She underwent penetrating keratoplasty and cataract extraction with posterior chamber intraocular lens implantation. We describe the clinical, histopathological and ultrastructural findings from the cornea. Histopathology of the corneal button revealed marked stromal thinning with degenerated keratocytes. The endothelial cells were multilayered, and immunohistochemical stains for cytokeratin were positive, findings consistent with posterior polymorphous dystrophy (PPMD). Transmission electron microscopy (TEM) was remarkable for the markedly thinned corneal stroma with loss of lamellar architecture and populated by degenerated keratocytes. Ultrastructural findings of well–developed desmosomes or microvilli, characteristic of PPMD, were absent on TEM. In vivo confocal microscopy on the fellow eye showed linear hyporeflective bands at the level of the endothelium consistent with PPMD. In addition, there were fine linear changes in the deep stroma and diffuse hyperreflectivity of the mid and superficial stroma with lack of identifiable keratocytes throughout. We believe that this is the first case reported in the literature to demonstrate histopathologic confirmation of PPMD in an Alport patient. However, the clinical, histologic, and ultrastructural characteristics are not typical of PPMD or any corneal dystrophy previously reported with Alport’s syndrome. This may represent a new phenotypic expression of PPMD, or may be a distinct clinicopathologic dystrophy, possibly caused by a different mutation at or near the Alport locus. Additional molecular and genetic studies may help shed light on this apparently new corneal dystrophy.
Keywords: degenerations/dystrophies • microscopy: electron microscopy • microscopy: confocal/tunneling