I'm like a lymph node and cyst factory. I have yet to have an MRI or CT scan that doesn't pick up a few small nodes because most people have a few small nodes in their body activated at any given time.
So why is your doctor testing? I asked my brother-in-law - an amazing GP - this very question once and he said doctors conduct tests for three big reasons: 1) the symptoms or other tests warrant it, 2) the patient seems very concerned, and 3) they could be legally liable if they don't test.
He said, "I can't feel what a patient is feeling, so I have to trust that what they're describing is real. " The problem is that people with HA tend to be more sensitive than other people - we focus on things that are really just normal body quirks; we get anxious, which causes MORE symptoms, and we tend to inflate the severity of our symptoms when we talk to our doctors (often in hopes that they'll test).
So your doctor isn't testing you because he's seen signs of lymphoma or because he suspects you have it... he's testing because you're panicking and because he has a legal obligation to.