Infiltration (medical)

Infiltration in a medical context is the process of cells or substances moving across a barrier, typically a tissue barrier, into a place they are not normally found, or in which they are typically found in lower concentrations. Infiltration may refer to normal physiological processes, such as the infiltration of certain immune cells into peripheral tissues. Infiltration may also refer to pathological processes, such as malignant tumor cells infiltrating new areas of the human body, or small particles infiltrating tissues, where they may cause damage or inflammation.