Typical electronegative electroretinography and nyctalopia as a presenting feature of systemic malignant melanoma

We report a unique case of a female who presented with unilateral disk edema, melanoma-associated retinopathy symptoms, and suggestive electroretinography findings preceding a diagnosis of metastatic melanoma of the pelvis. A 63-year-old female presented with complaints of seeing shimmering lights and nyctalopia, and underwent an extensive ophthalmological and electrophysiological examination. Best-corrected visual acuity was 20/20 in both eyes. Visual fields showed relative central scotomata and concentric narrowing. Slit-lamp and fundus examinations were normal. Rod-specific electroretinography responses were severely reduced, with electronegative maximal combined rod-cone responses and delayed cone responses with normal amplitude. Melanoma-associated retinopathy was suspected. Extensive systemic and internal evaluation revealed occult metastatic melanoma of the pelvis of unknown primary site.