Can melanoma look like a yellow bruise?

Get checked. Typically, a melanoma does not look like a yellow bruise. Melanoma usually is an irregular pigmented lesion that may be changing. However, if you have an area that looks like a yellow bruise that is persisting, i would encourage that you have it checked by your physician. It is always better to play it safe.
Not yellow. Melanomas are usually some shade of brown, from very dark (almost black) to lighter shades, and may be several densities. Yellow is not typical, and more often represents breakdown products of blood in a bruise. See your doctor who will ask about how long the discoloration has been there, which is important in deciding what it represents.