25 y old male. Feel node behind ear, 1 centimetre diameter, movable. How big does lymph node have to be before its serious? No other symptoms, Lymphoma?

Lymph node. marilyn, lymph nodes which are freely movable and less than 1 cm are usually considered not to be pathological. However, if this is a new finding to you, lymph node removal by an ENT surgeon and examined by pathologist is needed to be sure. Dr Hilliard.