because medical doubletalk is designed to soothe the patient, protect the provider, and achieve a good outcome in the vast majority of cases. however, because of people being overconfident/lazy/whatever, some simply diagnosed/treated conditions slip through the cracks and lead to a very, very bad outcome. your doctor made a decent call - if it looks like a lymphnode and acts like a lymphnode, then it probably is a lymphnode - so lets not traumatise the shit out of the patient by shoving in a very large biopsy needle and ordering an expensive test, lets just wait and see if the pesky bump keeps on acting like a lymphnode. hence, DO NOT NEGLECT YOUR FOLLOW UP APPOINTMENT.
also, to the guys betting, lymphnodes/cysts/lipomas look remarkably similar with the amount of info the doctor has at his disposal (ie no timeline of changes etc) so paying out bets is premature imo. im still in "wait and see" mode personally.