Maculopathy Linked to Light Chain Monoclonal Gammopathy: A Case Report.

Monoclonal gammopathies can produce a spectrum of ocular manifestations, most commonly paraproteinemic keratopathy, but retinal involvement, though rare, may be vision-threatening. We report a case of paraproteinemic maculopathy in a 49-year-old female with a history of hypertension and albuminuria, who presented with blurred vision and renal impairment. Examination revealed subretinal yellow infiltrates in the posterior pole with hyperautofluorescence on fundus autofluorescence and subretinal fluid with hyperreflective deposits above the retinal pigment epithelium on optical coherence tomography. Laboratory workup identified an excess of free kappa light chains in serum. A diagnosis of light chain deposition disease (LCDD) was made on the basis of a renal biopsy, and systemic therapy was initiated. At 5 months posttreatment, best-corrected visual acuity improved to 20/20 OU, with resolution of subretinal fluid, although sub-RPE deposits persisted. This case illustrates that monoclonal free light chains can induce maculopathy through RPE and choroidal depositions, mimicking other macular diseases. Early recognition and systemic treatment targeting the underlying plasma cell disorder are essential for visual recovery. Ophthalmologists should maintain a high index of suspicion for paraproteinemic maculopathy in patients with atypical serous macular detachments, particularly when the findings are bilateral or associated with subtle systemic signs, emphasizing the need for a multidisciplinary approach.