Of note: The areas most affected are the thumbnail or the big toenail. Subungual. Currently, the exact cause of development of Melanoma of Nail Unit is unknown. However. This isn't the case with melanoma under the nail matrix. (
But, a toenail melanoma is not caused in this way – in fact, there are no. You might think that it is just a brown spot under your toenail, but it does mean that you .
Other types of melanoma rarely arising under the nails are nodular melanoma. affects either a thumb nail or great toenail but any finger or toenail may be involved.. May cause thinning, cracking or distortion of the nail plate (nail dystrophy).