Biopsy of lymphnodes-found nothing first time 2nd biopsy of lymphnode -tissue sample what are they looking for and what will they find?

See below: The doctor taking the biopsy must feel there is a reason that was not found with the origianl biopsy i need more information about the first but obviously the doctor is looking for an answer he did not get with the first-many causes exist for enlarge lymnph node including infections and cancer and enlargement from an infection somewhere elkse in the body.