Melanonychia with pigmentation of the proximal nail fold.:671 This is an important sign of subungal melanoma although is not an infallible predictor. Periungual hyperpigmentation occurs in at least one nonmelanoma skin cancer, Bowen's disease of the nail unit. Hyperpigmentation of the nail bed and matrix may reflect through the "transparent" nailfolds simulating Hutchinson's sign.
^Hutchinson J. "Clinical report on herpes zoster frontalis ophthalmicus (shingles affecting the forehead and nose)." Ophthalmic Hospital Reports and Journal of the Royal London Ophthalmic Hospital, London, 1864, 3(72):865–866; 1865, 5:191.