Hodgkin lymphoma is a cancer. Like other cancers, it starts when cells grow out of control, multiplying and crowding other normal cells.

Hodgkin lymphoma starts in the lymph system, which contains the lymph nodes. The lymph system is part of the body’s immune system that protects it from infections and diseases.

Lymph nodes contain the lymph fluid that carries white blood cells through a network of thin tubes spreading through the body.

Hodgkin differs from other lymphomas in an important way: Hodgkin cancer cells only make up a small part of the cells in a lymph node. The rest of the cells are normal cells. (In other lymphomas, cancer cells make up most of the cells in a lymph node.)

Hodgkin lymphoma can usually be cured if it is found early and treated soon.