Malignant melanoma is the most dangerous type of skin cancer. Melanomas beneath the fingernail appear as a black or bluish black discoloration. This type of malignancy spreads (metastasizes) readily.
A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network (7/26/2011).