Peripheral hypertrophic subepithelial corneal degeneration presenting with bilateral nasal and temporal corneal changes

Successful surgical management of post-penetrating or deep lamellar keratoplasty Acquired Corneal Sub-Epithelial Hypertrophy (ACSH): A case series

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The differential diagnosis of superficial corneal opacities is challenging.

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It includes 3 described overlapping entities: SND, PHSCD, and Acquired Corneal Sub-Epithelial Hypertrophy (ACSH).

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Our case series match the newly proposed entity of ACSH.

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ACSH should be accurately identified following keratoplasty to be successfully managed by simple surgical peeling without corneal re-grafting.

Introduction

Acquired Corneal Sub-Epithelial Hypertrophy (ACSH) has been described in patients with peripheral superficial corneal opacities following penetrating keratoplasty and might present similar to Salzmann’s nodular degeneration (SND) or peripheral hypertrophic sub-epithelial corneal degeneration (PHSCD). We describe the clinical presentation, topographic findings and the surgical outcome of three cases, which fit the appearance and characteristics of ACSH.

Presentation of cases

Three patients (3 eyes) with paracentral or peripheral corneal opacification were reviewed to describe their clinical examination (SL), morphology of the opacity (depth, diameter and density) and document their topographic changes before and after surgical intervention by peeling of the epithelium with or without superficial keratectomy under the microscope in addition to brief description of their histopathological examination.

Discussion

All 3 cases were secondary to corneal procedures [Penetrating keratoplasty (PKP) in 1 for pseudophakic bullous keratopathy and deep anterior lamellar keratoplasty (DLK) in 2 for advanced keratoconus]. All cases presented with reduced vision, astigmatic changes in topography or manifest refraction. The visual acuity, symptoms, and topographical findings all improved after treatment. Histopathologically, all cases fit the newly described entity of ACSH.

Conclusion

Careful clinical judgement guided by corneal topography are needed for proper the diagnosis of acquired corneal opacification that results in reduction of vision to identify ACSH from other similar conditions (PHSCD and SND). Peeling of the thickened epithelial and sub-epithelial tissue is curative avoiding the need for corneal re-grafting.

Successful Treatment of Corneal Opacification with Associated Thickened Epithelium by Simple Peeling: Acquired Corneal Subepithelial Hypertrophy (ACSH)

Purpose

To study clinical and histopathological findings of corneal opacification caused by thickened epithelium leading to reduced vision and topographical changes and to evaluate the outcome of its removal.

Methods

Twelve patients (17 eyes) with central, paracentral or peripheral corneal opacification were reviewed to obtain their visual acuity, describe their slit lamp (SL) appearance (depth, extent and density) and document their topographic changes before and after peeling of the epithelium under SL or surgical removal under the microscope. Specimens of six cases were available for histopathological examination and immunohistochemical staining.

Results

Most of the eye opacifications were secondary to corneal procedures in 10 [Penetrating keratoplasty (PKP) in 7 for congenital glaucoma, keratoconus or adherent leukoma – usually over graft-host junction –, Photorefractive keratectomy (PRK) in 2 and Phototherapeutic keratectomy in one], chronic inflammation following trachoma or non-specific causes (3), and herpetic scar (1). Three cases were considered to be idiopathic. All cases presented with decreased vision, astigmatism or changes in topography or refraction. Their vision, clinical symptoms and topography improved after treatment. Histopathologically, all six cases shared findings that are similar to what have been described as peripheral hypertrophic subepithelial corneal degeneration (PHSCD) rather than Salzmann’s nodular degeneration. None of the cases showed inflammation or subepithelial pannus formation in the excised tissue. However, our cases did not fit into the diagnosis of PHSCD because of the location of the corneal opacification (being peripheral in 41% of the corneas, the presence of underlying primary etiologic factors in 82% of the eyes and the bilateral occurrence in 5 patients.

Conclusions

Meticulous SL examination aided by corneal imaging may accurately diagnose and determine the depth of corneal opacification as a cause for reduced vision. Histopathologically, the removed tissue is similar to PHSCD, but cases differ in their clinical profile. Peeling the thickened epithelial/subepithelial tissue is curative in most patients, improves visual and clinical outcome and avoids unnecessary corneal grafting.

[Surgical removal of Salzmann's nodules using intraoperative mitomycin C]

Salzmann's nodules comprise a heterogeneous group of greyish superficial corneal opacities. A substantial percentage is most likely caused by dystrophies. This could explain the recurrences after surgical removal. The Eye Center of the University Hospital Freiburg has been using mitomycin C intraoperatively during surgical removal of Salzmann's nodules since 2007 to prevent recurrences. We recently performed an uncontrolled prospective trial to evaluate this approach and also reviewed the literature. Worldwide, a total of 38 eyes have been treated with mitomycin C during surgery for Salzmann's nodules. No recurrences have been reported so far with follow-up exceeding at least 2 years in almost all eyes. No severe side effects have been observed to date. We therefore think that mitomycin C during surgery for Salzmann's nodules is advisable despite the lack of evidence from a randomized clinical trial. However, all patients must consent to the off label use of mitomycin C.