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Dépôts Cornéens Cristallins Liés A Une Gammapathie Monoclonale De Signification Indéterminée Traités Par De l'Acide N-Acetyl Aspartyl Glutamique Topique

To report the clinical, diagnostic and therapeutical findings of a patient with bilateral corneal deposits caused by an underlying monoclonal gammapathy of undetermined significance.

Slit-lamp biomicroscopy, confocal microscopy and additional serological tests were performed on a 40-year-old man with bilateral crystalline corneal deposits presenting with bilateral ocular irritation and photophobia.

The patient was diagnosed as having bilateral crystalline corneal deposits believed to be linked to a hypergammaglobulinaemic state leading to the diagnosis of an underlying MGUS based on elevated levels of serum immunoglobulin G. Confocal microscopy showed hyperreflective deposits predominantly in the epithelium and subepithelial layer. The patient was initially treated with corticosteroid eyedrops with rapid resolution of symptoms but leading to steroid dependence. Introduction of topical N-acetylaspartylglutamic acid allowed a rapid corticosteroid withdrawal and resolution of ocular symptoms.

Corneal crystalline deposits have been described in the litterature to occur in a variety of hypergammaglobulinaemic states or lymphoproliferative affections includind IgG MGUS with a very low incidence and can be the first clinical signs of these general disorders. The intra-corneal paraprotein deposit mechanisms are plural, as like through the tear film, by way of the corneoscleral limbus vasculature, and by diffusion in the cornea from aqueous humor from the anterior chamber.

Ophthalmologists should be aware of corneal crystalline deposits as potential warning signs of monoclonal gammapathy. Treatment of this ocular condition can be challenging. The complement system plays important roles in a variety of chronic ocular diseases. Our hypothesis is that immunoglobulin deposits activate complement cascade, leading to ocular surface chronic inflammation. Topical NAAG as a complement-activatory inhibitor, can be useful in treating ocular surface inflammation caused by paraprotein corneal crystalline deposits.