Monoclonal gammopathy of undetermined significance
B. Additional laboratory workup
When encountering asymmetrical, bilateral anterior and posterior stromal corneal lesions, clinicians should consider systemic causes (infectious, autoimmune, and hematologic) and pursue laboratory workup. Salzmann nodular degeneration was deemed less likely, given the variable lesion depth and lack of surface elevation. The following diagnostic workup was pursued: complete blood cell count, comprehensive metabolic panel, serum and urine protein electrophoresis, HIV, cytomegalovirus, Epstein-Barr virus, herpes simplex virus/herpes zoster virus, Lyme antibody titers (IgG/IgM), rapid plasma reagin, fluorescent treponemal antibody absorption, QuantiFERON Gold, angiotensin-converting enzyme, lysozyme, antinuclear antibody, rheumatoid factor, cyclic citrullinated peptide, antineutrophil cytoplasmic antibodies, and anti-SSA (Ro)/anti-SSB (La) antibodies. Results revealed an elevated γ globulin M spike (0.8 g/dL), cytomegalovirus IgG, and herpes simplex virus IgG. Notably, herpes simplex virus IgM, Epstein-Barr virus, and other autoimmune laboratory values were negative. The abnormal serum proteins prompted referral to a hematologist. Monoclonal gammopathies encompass a spectrum of diseases, including multiple myeloma and monoclonal gammopathy of undetermined significance (MGUS). While multiple myeloma is one of the most common hematologic malignancies, a forme fruste, premalignant stage-termed MGUS may precede it.1,2 Estimated to have a prevalence of 3% to 4% in individuals older than 50 years, MGUS progresses to multiple myeloma at a rate of 0.5% to 1% per year.2 Traditionally, it has been considered an asymptomatic disease stage and requires the absence of hypercalcemia, kidney failure, anemia, and bone lesions.2,3 Although visual symptoms are minimal in MGUS, ocular findings may be the first sign of systemic disease, providing ophthalmologists with an important role in diagnosing underlying disease.