Lymph node metastasis in melanoma, light micrograph. Melanoma is a type of skin cancer that arises in melanocytes, the skin cells that produce melanin pigment. It is also known as malignant melanoma and cutaneous melanoma. Melanomas can also develop in mucus membranes in locations such as eyes, mouth, genitals, and anus, but they are rarer than melanomas of the skin. This light photomicrograph shows melanoma that has metastasized to a lymph node. The melanoma cells are large cells with abundant cytoplasm containing brown pigment. The smaller cells at the periphery are normal lymphocytes.