Liver cancer, gross specimen. Typical pigmented tumours resulting from malignant melanoma in the liver, metastasized from melanoma of the skin. Melanoma is a cancer arising from melanocytes, the pigment cells in the skin. Metastasis is the transfer of disease from one organ or part to another not directly connected with it. All malignant tumours have the capacity to metastasize. The commonest malignant growths found in the liver do in fact arise from cancers in other organs. Once a cancer has spread beyond its site of origin, the prognosis is poor.