Lines on nails: Part 1

Subungual melanoma is very rare. The Skin Cancer College Australasia database suggests that you will see 600 invasive melanomas for every subungual melanoma. However, you are more likely to see a fungal lesion like this first. A dermatoscope image helps distinguish the two, with the melanoma showing lines of pigment of varying colours and thickness while this is usually absent in a fungal infection. Collecting some nail clippings for culture helps in arriving at the correct diagnosis. The pink colour is nail polish.
See for other images.