<s>[INST]I have an 8 year-old Lhasa Apso, cream-colored. He has developed a small movable lump on his side, which a few weeks later became pigmented. On the other side, he has just developed another small movable lump, with pigmentation starting. Is this melanoma?[/INST]Difficult to say.  If you have lesions on your skin that you are worried about, it is very reasonable to see a dermatologist (or a veterinarian in this case) for a biopsy. The only way to tell for sure if a lesion is malignant or not is to look at the cells under a microscope.  A biopsy entails removing either the entire lesion, or taking a piece of it and then sending it to a pathologist who looks at the cells under a microscope and is able to tell what they are.</s>