Lymphangiogenesis is the formation of lymphatic vessels from pre-existing lymphatic vessels in a method believed to be similar to angiogenesis (blood vessel development). Lymphangiogenesis plays an important physiological role in homeostasis, metabolism and immunity. Impaired or excessive lymphatic vessel formation has been implicated in a number of pathological conditions including neoplasm metastasis, oedema, rheumatoid arthritis, psoriasis, lymphangiomatosis and impaired wound healing.