Melanonychia: the importance of dermatoscopic examination and of nail matrix/bed observation

Melanonychia, from the Greek melaina, means black and is the result of an increased deposition of melanin on the nail plate, originating in the nail matrix. It may have different causes, including subungueal melanoma, making early etiologic diagnosis very important.Univ Fed Sao Paulo, Escola Paulista Med, Extensao Univ,Curso Especializacao Dermatol, Area Elet Dermatoscopia,Sociedade Brasileira Derm, Sao Paulo, BrazilSanta Casa Misericordia Rio de Janeiro, Inst Dermatol Prof Rubem David Azulay IDPA, Rio De Janeiro, BrazilArmed Forces Inst Pathol, Washington, DC 20306 USAUniv Fed Rio de Janeiro, Dept Pathol, Rio De Janeiro, BrazilUniv Sao Paulo, Sao Paulo, BrazilInst Dermatol Prof Rubem David Azulay IDPA, Sao Paulo, BrazilPontificia Univ Catolica Rio de Janeiro, Rio De Janeiro, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Extensao Univ,Curso Especializacao Dermatol, Area Elet Dermatoscopia,Sociedade Brasileira Derm, Sao Paulo, BrazilWeb of Scienc