A case of nail apparatus melanoma in situ studied over a long follow-up period

Abstract

A 25-year-old woman noticed a black-colored line on her right ring fingernail that had been present since she was 16 years old. The 5 mm-wide brownish streak was observed on the nail when she visited our hospital for the first time at the age of 19 years. The micro-Hutchinson sign was positive. The pigmented band became broader, while its color became darker and then lighter during the follow-up observations. After a 3.5-year absence, she visited the hospital again at the age of 25 years as the nail pigmentation became darker with a crack at the tip of the nail. We diagnosed the patient with malignant melanoma in situ, and excised the lesion. Histological findings of the lesion were compatible with those of nail apparatus melanoma in situ. We report this case of nail apparatus melanoma in situ, followed-up for a long time, with clinical observation of its dermoscopic features, along with a literature review.[Skin Cancer (Japan) 2016 ; 31 : 249-254]