Lymphoma is a cancer of the lymphocytes, a type of cell that forms part of the immune system. Typically, lymphoma is present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage of the disease. These malignant cells often originate in lymph nodes, presenting as an enlargement of the node (a tumor). It can also affect other organs in which case it is referred to as extranodal lymphoma. Extranodal sites include the skin, brain, bowels and bone. Lymphomas are closely related to lymphoid leukemias, which also originate in lymphocytes but typically involve only circulating blood and the bone marrow (where blood cells are generated in a process termed haematopoesis) and do not usually form static tumors. There are many types of lymphomas, and in turn, lymphomas are a part of the broad group of diseases called hematological neoplasms.

Thomas Hodgkin published the first description of lymphoma in 1832, specifically of the form named after him, Hodgkin's lymphoma. Since then, many other forms of lymphoma have been described, grouped under several proposed classifications. The 1982 Working formulation classification became very popular. It introduced the category non-Hodgkin lymphoma (NHL), divided into 16 different diseases. However, because these different lymphomas have little in common with each other, the NHL label is of limited usefulness for doctors or patients and is slowly being abandoned. The latest classification by the WHO (2008) lists 70 different forms of lymphoma divided in four broad groups.

Vivian Patrick Campbell (born 25 August 1962) is a Northern Irish rock guitarist who is a member of Def Leppard and was a member of Thin Lizzy from May 2010 to November 2011. Prior to joining Def Leppard in April 1992, he had been a member of Whitesnake, Sweet Savage, Trinity, Riverdogs, and Shadow King. He first rose to prominence in 1982 as the original guitarist of the band Dio.

Campbell was born in Lisburn, County Antrim, Northern Ireland and attended Rathmore Grammar School. He began playing guitar at the age of 12. He has played for Sweet Savage, Dio, Trinity, Whitesnake, Riverdogs, and Shadow King. He also played on Lou Gramm's (from Foreigner) second solo album Long Hard Look.

Sweet Savage was a NWOBHM band that Campbell joined when he was 15. The band members in Sweet Savage included Campbell on guitar, Trev Fleming on guitar, David Bates on drums and Ray Haller on bass and vocals. The band influenced Metallica, who covered the song "Killing Time" on their Garage Inc. covers album. In 1981 they released an e.p. consisting of four BBC radio sessions and their first single "Take No Prisoners". "Take No Prisoners" included the song "Killing Time". Much later in the late 90's after Metallica covered "Killing Time", there was interest in Sweet Savage and they released an album without him. Campbell left Sweet Savage in early 1983 to join Dio after Jake E. Lee original Dio guitarist was offered Randy Rhoads spot as Ozzy Osbourne's lead guitarist on December 1982, when Ronnie James Dio was forming his own band. Vivian Campbell later guested on Sweet Savage's cover of the Thin Lizzy song "Whiskey In The Jar".