DefinitionLymphoid hyperplasia is a rapid increase in the number of normal cells (called lymphocytes) that are contained in lymph nodes.These cells increase in number to help lymph nodes prevent bacteria, viruses, and other types of germs from entering the bloodstream.Alternative NamesLymphoid hypertrophyReferencesArmitage JO. Approach to the patient with lymphadenopathy and splenomegaly. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 174.