ABSTRACT
A 35-year-old woman has noticed a painless swelling on the left side of her neck, which has been present for over 4 weeks. It is slowly enlarging. There is no relevant past medical history and no history of fever. Physical examination reveals a single small (21 cm × 0.5 cm) mobile lymph node in the left anterior triangle of the neck. There are no other palpable nodes, and the liver and spleen are not palpable. Investigation shows
