 It may also be generalised, which might suggest infection, connective tissue or autoimmune disease, or a malignancy of blood cells such as a lymphoma or leukaemia.Rarely, depending on location, lymph node enlargement may cause problems such as difficulty breathing, or compression of a blood vessel (for example, superior vena cava obstruction).Enlarged lymph nodes might be found because they felt as part of a medical examination, or found on medical imaging.