When lymphocytes develop abnormally, or they don’t die when they should, they can collect in the lymph nodes and form tumours (cancers). Although there are many different types of lymphoma, they are broadly categorised as either Hodgkin or non-Hodgkin lymphoma. The cause of lymphoma isn’t known, even though it’s the fifth most common blood cancer in adults and the third most common cancer in children in Australia. Read More > A lymphoma diagnosis can lead to more questions than answers. Lymphoma Australia is working hard to ensure Australians can learn more about this type of cancer.