Hodgkin lymphoma is cancer that begins in the lymph system in white blood cells called lymphocytes. When these cells become abnormal, they grow without control and may form lumps of tissue called tumors.
The most common type of Hodgkin lymphoma is called classical Hodgkin lymphoma. The cancerous tumors (lymphomas) in classical Hodgkin lymphoma contain Reed-Sternberg cells. Non-Hodgkin lymphomas don't have these cells.
Non-Hodgkin lymphoma is a type of cancer that happens when cells in your lymph system grow abnormally and out of control. The cells can form a mass, called a lymphoma. They can also spread to other parts of your body.
Treatment can cure some people and may allow others to live for years.