Yes, it happened in my case. Although my scan was clear mid CHOP chemo I had some reactive lymph nodes later, after 6 rounds of Chemo . They were small and The biopsy was negative and the subsequent scan showed that they were even smaller and less reactive and the scan after that one was clear. So apparently my lymph nodes had reacted to an infection.

AnnaBates,
Thanks for your reply. Once you've had "bad" lymph nodes, it messes with your thinking. Your info was helpful.