Illuminating Blurry Vision: Visualization of Corneal Protein Deposition With Immunofluorescence in Two Illustrative Case Reports.

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic, premalignant disease with a progression rate of 0.5%-1% per year to multiple myeloma. It can rarely present with significant ocular symptoms in the context of crystalline keratopathy, necessitating medical and surgical interventions. Lattice corneal dystrophy Type I (LCD-1), a rare inherited disorder caused by mutations of TGFBI, manifests with amyloid deposition within the corneal stroma and causes visual impairment. Here, we pictorially highlight protein deposition using immunofluorescence in two representative cases, both having undergone penetrating keratoplasty for blurry vision.

METHODS

Medical records were reviewed. Hematoxylin and eosin, special staining, immunohistochemistry, and immunofluorescent techniques were performed. A literature review was performed.

RESULTS

Case 1: Eosinophilic accumulations of the cornea were highlighted with PAS-D and IgG-kappa by immunohistochemistry, whereas immunofluorescence (IF) technique demonstrated IgG-kappa (2+) staining in the stroma with rare globules in the epithelium. Case 2: Amorphous, eosinophilic deposits within the corneal stroma were congophilic with apple-green birefringence on polarized light. Thioflavin T highlighted the amyloid through immunofluorescence. Mass spectrometry detected a peptide profile consistent with ATGFBI-type amyloid deposition.

CONCLUSION

Immunofluorescence can be helpful in the workup of corneal protein deposition, such as MGUS-related crystalline keratopathy and LCD-1.