Two kinds of Hutchinson's sign, benign and malignant

Me examined 6 subungual melanomas in situ and 18 melanocytic nevi and compa red pigmentation of the nail plates and hyponychium with the use of a derma toscope. Hutchinson's sign on the hyponychium was not always evidence of su bungual melanoma because it can be seen in both diseases. However, there a as a wide difference in their dermatoscopic features. We believe that obser vation of pigmentation on the hyponychium with the use of a dermatoscope co ntributes to the precise diagnosis of subungual melanoma.