Melanoma-associated retinopathy during pembrolizumab treatment probably controlled by intravitreal injections of dexamethasone.

Melanoma-associated retinopathy (MAR) is a rare paraneoplastic syndrome due to antibodies targeting bipolar retinal cells. Its evolution, particularly in patients treated with immune checkpoint inhibitors (ICI), is currently poorly understood. In the few cases published, patients' visual function got worse when these molecules were prescribed. Here, we present a case of a patient with severe MAR treated with an ICI for melanoma progression. A 68-year-old woman with a history of melanoma of the palpebral conjunctiva presented with sudden and gradually worsening visual disturbances. Simultaneously, a metastatic evolution of the melanoma was diagnosed and surgically treated exclusively. Visual acuity assessment, static automated perimetry and ERG results lead to the diagnosis of MAR. Since systemic corticosteroid therapy did not improve her symptoms, repeated intraocular corticosteroid injections were performed with a positive outcome. Later on, metastatic progression of the patient's melanoma led to the introduction of pembrolizumab, an ICI targeting PD-1. Immunotherapy has changed the prognosis of patient affected by metastatic melanoma, but these molecules may induce various immune-related adverse effects. In our case, intraocular corticosteroid injections were still performed simultaneously. Visual acuity assessment, static automated perimetry and ERG were performed during the course of this treatment. Full-field ERGs results suggested the possibility that the ophthalmologic treatment might restore the patient's retinal function despite the continued immunotherapy. We report the first case of MAR with a positive outcome after 1 year of ICI, possibly thanks to intravitreal corticosteroid therapy.