Metastasis can occur along tissue planes, capillaries, or lymph vessels. Spread to the skin can also occur through implantation or 'seeding'—for example in the abdominal wall during surgery for ovarian and colorectal tumours. Tumours commonly associated with the development of malignant wounds include tumours of the breast, head and neck, kidney, lung, ovary, colon, penis, and bladder, as well as lymphoma and leukaemia. The management of the symptoms of malignant wounds should always be focused on the person's quality of life, and priorities should therefore be based on problems that are identified by the patient as being the most troublesome, combined with the clinical concerns of health professionals. The most frequently reported of these wound-related signs and symptoms are odour, exudate, pain, and bleeding. Malignant wounds can have a significant impact on the psychological and social well being of people. Bleeding can occur from the wound spontaneously or as a result of trauma during dressing changes.