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You have had one or more lymph nodes in your groin removed.

Fluid forms in tissue throughout the body every day. This tissue fluid is the lymph. The lymph is carried around the body by lymph vessels. The lymph vessels run around the entire body and are connected to blood vessels. At some points, there are lymph nodes along the lymph vessels. Pathogens are rendered harmless in the lymph nodes, for example. Lymph nodes are small, bean-shaped structures. They are part of the body’s defense system.

You have had your lymph nodes surgically removed. To do this, your skin was cut open.

You have had one or more sentinel lymph nodes removed. The lymph from an organ usually flows first through a sentinel lymph node before reaching other lymph nodes. To detect the sentinel lymph node, a radioactive substance and special blue dye were injected into the relevant organ. An observation was then made of which lymph node the radioactive substance and special blue dye spread to first. To do this, a device that measures radioactivity was also used.