extravasate

Extravasation is the leakage of a fluid out of its container. In the case of inflammation, it refers to the movement of white blood cells from the capillaries to the tissues surrounding them (leukocyte extravasation), also known as diapedesis. In the case of malignant cancer metastasis it refers to cancer cells exiting the capillaries and entering organs. It is frequently used in medical contexts, either referring to urine, or to blood.