Had excisional biopsy everything came back clear. still have swollen lymph nodes in neck. same size. why is that? was told there reactive nodes

? mononucleosis: When a node in any node bearing area is enlarged, a biopsy must reveal cause of node alteration. If FNA performed, findings can be neg. since architecture of node must be examined, Excisional bx needed and if totally normal a second area must be examined to look for I.M. or lymphoma. If inflammation , source must be defined.