Lattice-like paraproteinemic keratopathy (PPK) of monoclonal gammopathy of undetermined significance (MGUS).

To cite: Gama I, Almeida L. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2016-218031 DESCRIPTION A male patient aged 71 years presented with a history of progressive visual loss in the past 3 years. Ophthalmological evaluation showed a bestcorrected visual acuity of 20/200 bilaterally and the presence of bilateral linear lattice-like corneal opacities similar to lattice dystrophy (LD) and dense nuclear cataracts at slit lamp examination (figure 1). There was no family history of ocular diseases. Serum protein electrophoresis included in the systemic investigation showed a band in the γ-globulin fraction (figure 2). Nephelometry detected an increased level of κ light chains—75.6 mg/dL (normal: 3.3–19.4 mg/dL) and a normal level of λ light chains—14.4 mg/dL (normal: 5.7–26.3 mg/dL) and an increased κ/λ ratio of 5.25 (normal: 0.26– 1.65). Immunoelectrophoresis also confirmed the IgG-κ gammopathy. Myelogram showed 2% of plasma cells. No lytic bone lesions were present on plain X-ray. No mutations were found on transforming growth factor β-induced gene (TGFBI) nor on gelsolin gene sequencing. The diagnosis of lattice-like paraproteinemic keratopathy (PPK) secondary to monoclonal gammopathy of unknown significance (MGUS) was made. The patient was subsequently followed-up in Haematology. Cataract surgery followed by corneal transplant was proposed. MGUS-induced PPK is rare and is caused by corneal immunoglobulin deposition. 2 Lattice-like PPK secondary to MGUS is even rarer and only eight cases have been reported. 3 PPK can simulate LD. 3 The abnormalities on SEP and subsequent investigations lead to the MGUS diagnosis. The negative family history and the absence of TGFBI/gelsolin mutations excluded LD and Meretoja syndrome. The late-onset lattice-like corneal pathology, without family history nor TGFBI/gelsolin gene mutations should raise the suspicion of PPK leading to the necessary clinical and laboratorial investigations.