Signature of an assassin
Melanoma of the nail-matrix is rare with a reported incidence of about 0.1/100,000;1 that is one in a million, (compared to approximately 49/100,000 for invasive melanomas in Australia).2
The reported mortality rate is higher than melanomas in general, but it is not known whether this is due to later diagnosis or more aggressive tumour behaviour.3
The actual malignant melanocytes in subungual melanoma are concealed beneath the proximal nail fold, but the pigment produced by these melanocytes creates a distinctive signature – longitudinal bands of pigment stretching from the proximal nail fold to the free edge of the nail plate.
While such bands of pigment (longitudinal melanonychia) can also be produced by naevi, certain drugs, ethnic pigmentation and so on, only in melanoma do these parallel lines vary in width, spacing and colour (chaos).4
Any new nail