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Table of Contents
CASE REPORT
Year : 2021  |  Volume : 3  |  Issue : 1  |  Page : 8

Polymorphic amyloid degeneration of the cornea: A Clinical and In vivo confocal microscopy study


1 Department of Ophthalmology and Vision Science, University of California, Sacramento, CA, USA
2 Department of Ophthalmology, Pontificia Universidad Católica de Chile, Santiago, Chile

Date of Submission22-Sep-2020
Date of Acceptance16-Nov-2020
Date of Web Publication12-Mar-2021

Correspondence Address:
Dr. Milad Modabber
Department of Ophthalmology and Vision Science, University Of California, Sacramento, Ca
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/pajo.pajo_52_20

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  Abstract 


We report a rare case of polymorphic amyloid degeneration (PAD) with in vivo confocal microscopy and anterior segment optical coherence tomography (AS-OCT). A 74-year-old female presented to our service for suspected Fuchs corneal dystrophy. Her best-corrected visual acuity was 20/25 right eye (OD) and 20/20 left eye (OS). Slit-lamp biomicroscopy revealed bilateral punctate, refractile deposits in the deep stroma in an annular distribution with relative sparing of the central cornea. The remainder of the ocular examination was within expected limits. Central pachymetry was 546 μ OD and 535 μ OS. AS-OCT demonstrated focal hyper-reflective lesions in the deep stroma. Specular microscopy showed normal endothelial cell count and morphology. Confocal microscopy highlighted bright, enhancing punctate lesions in both the anterior stroma and deep stroma with normal intervening spaces. The patient was managed conservatively. Altogether, PAD is a rare, sporadically inherited condition that presents in the elderly. Confocal microscopy can aid in the diagnosis.

Keywords: Amyloid, confocal microscopy, polymorphic amyloid degeneration


How to cite this article:
Modabber M, Cortés DE, Mannis MJ. Polymorphic amyloid degeneration of the cornea: A Clinical and In vivo confocal microscopy study. Pan Am J Ophthalmol 2021;3:8

How to cite this URL:
Modabber M, Cortés DE, Mannis MJ. Polymorphic amyloid degeneration of the cornea: A Clinical and In vivo confocal microscopy study. Pan Am J Ophthalmol [serial online] 2021 [cited 2021 Apr 21];3:8. Available from: https://www.thepajo.org/text.asp?2021/3/1/8/311125




  Introduction Top


Polymorphic amyloid degeneration (PAD) is a rare bilateral corneal degeneration with only five cases reported in the literature. It is characterized by punctate refractile deposits in the deep stroma. Herein, we report a case of bilateral PAD with in vivo confocal microscopy and anterior segment optical coherence tomography (AS-OCT), as well as offer a review of the literature.


  Case Report Top


A 74-year-old female was referred to the University of California Davis Cornea service for surgical management of Fuchs corneal dystrophy. Her past medical history entailed Type II diabetes mellitus that was controlled with insulin and a remote history of estrogen-receptor-positive breast cancer, treated with hormone-based chemotherapy. Her past ocular history included bilateral pseudophakia and primary open-angle glaucoma, status-post selective laser trabeculoplasty both eyes (OU) There was no history of familial eye disease. She did not complain of decreased or diurnally fluctuating vision. Her best-corrected visual acuity was 20/25 with −2.50 +1.25 × 96 in the right eye (OD) and 20/20 with +0.25 +1.50 × 82 in the left eye (OS). External and ocular motility examinations were normal. Pupils were equal and reactive to light, and there was no relative afferent pupillary defect. The intraocular pressure was 21 mmHg OD and 18 mmHg left eye OS. Corneal sensation was intact bilaterally.

Slit-lamp biomicroscopy revealed bilaterally symmetric, punctate refractile opacifications in the deep, predescemet stroma in a distinctly annular distribution with relative sparing of the central cornea, best appreciated on retro illumination [Figure 1]. The epithelium, Bowman layer, and endothelium were normal. The anterior chamber was deep and quiet. In the right eye, there was a well-positioned posterior chamber intraocular lens (IOL) with an open capsule, and in the left eye, a sulcus IOL with partial iris capture and an open capsule. The posterior segment examination was notable for moderate optic nerve cupping, with a cup/disc (C/D) ratio of 0.65 OD and 0.7 OS, but with no drance hemorrhage or focal notching.
Figure 1: Anterior segment photographs of the right (a) and left (b) eyes shown in retroillumination, demonstrating numerous deep punctate and filiform opacities in an annular distribution with relative sparing of the central cornea

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Central pachymetry (Pachmate 2, DHG Technology Inc., EXTON, PA, USA) was 546 μ OD and 535 μ OS. AS-OCT (Spectralis, Heidelberg Engineering Inc., Franklin, MA, USA) demonstrated focal hyper-reflective lesions in the deep stroma [Figure 2]. Specular microscopy confirmed normal endothelial morphology and cell count (2674 cells/mm2 OD, 2681 cells/mm2 OS). Confocal microscopy (Rostock Cornea Module/HRT III, Heidelberg Engineering, Heidelberg, Germany) demonstrated bright, enhancing punctate and fusiform opacities in both the anterior and posterior stroma, with unaffected intervening spaces [Figure 3]. The patient was diagnosed with isolated bilateral PAD. Since these deposits were visually insignificant, the patient was managed conservatively.
Figure 2: Anterior segment optical coherence tomography images of the right (a) and left (b) eyes, showing focal paracentral hyperreflective lesions in the deep stroma

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Figure 3: Confocal microscopy images of (a) right eye, showing multiple fusiform deposits in the deep corneal stroma; (b) left eye, an oblique image demonstrating the corneal epithelium and the subepithelial plexus on the bottom right portion and the anterior stroma in the top left portion, highlighting multiple punctate, fusiform opacities within the anterior stroma; (c) left eye, oblique section of deep stromal keratocytes on the top half and endothelial cells in the bottom half, showing fusiform hyper-reflective opacities in the deep stroma and pre-Descemet's layer

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  Discussion Top


PAD is a rare condition, with only a few reported cases in the literature.[1],[2],[3],[4],[5] This condition was first reported by Thomsitt and Bron as “polymorphic stromal dystrophy.”[2] Subsequently, Mannis et al. conducted a histopathologic analysis of affected corneas and observed amorphous deep stromal amyloid deposits that stain positively with Congo red stain and demonstrate apple-green birefringence under polarized light. They re-defined the disorder as a degenerative phenomenon rather than a stromal dystrophy.[3]

PAD is a nonhereditary primary localized amyloidosis.[3] It typically presents in the elderly and does not have a sex predilection. It does not progress, and affected patients remain visually asymptomatic. The clinical examination demonstrates polymorphic glass-like punctate and filamentous opacities, most notably observed in the deeper, predescemet layers of corneal stroma with normal intervening spaces and often in an annular distribution.[3] The differential diagnosis includes lattice dystrophy, as well as the corneal deposits of dysproteinemias and posterior polymorphous corneal dystrophy. Treatment is typically not required unless vision is affected.

A case series by Woodward et al. evaluated the confocal microscopic findings of PAD.[1] The authors noted discrete, punctate, highly reflective deposits of variable intensity on confocal microscopy, which correlated well with the clinically apparent discrete punctate opacifications. Similarly, we found that while these deposits were clinically observed only in the deep stroma, confocal microscopy demonstrated their presence in the Descemet membrane as well as in the anterior corneal stroma. The size and morphology of these deposits corresponded well to the histopathological and electron microscopic analysis as reported by Mannis et al.[3] Combined presentation of amyloid degeneration with posterior crocodile shagreen has also been observed.[1],[4] However, the causative basis for this association remains unclear.


  Conclusion Top


We report a rare case of bilateral PAD. The confocal microscopic findings correlate well with the clinical examination as well as previous pathologic analysis of this corneal degeneration. This report highlights the utility of confocal microscopy in aiding in the diagnosis and understanding of this condition.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Woodward M, Randleman JB, Larson PM. In vivo confocal microscopy of polymorphic amyloid degeneration and posterior crocodile shagreen. Cornea 2007;26:98-101.  Back to cited text no. 1
    
2.
Thomsitt J, Bron AJ. Polymorphic stromal dystrophy. Br J Ophthalmol 1975;59:125-32.  Back to cited text no. 2
    
3.
Mannis MJ, Krachmer JH, Rodrigues MM, Pardos GJ. Polymorphic amyloid degeneration of the cornea. A clinical and histopathologic study. Arch Ophthalmol 1981;99:1217-23.  Back to cited text no. 3
    
4.
Krachmer JH, Dubord PJ, Rodrigues MM, Mannis MJ. Corneal posterior crocodile shagreen and polymorphic amyloid degeneration. Arch Ophthalmol 1983;101:54-9.  Back to cited text no. 4
    
5.
Nirankari VS, Rodrigues MM, Rajagopalan S, Brown D. Polymorphic amyloid degeneration. Arch Ophthalmol 1989;107:598.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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