Diagnosed With Diverticulitis. Chest X-ray Done. Possibility Of Retroperitoneal Or Gastrointestinal Cancer?

Question : My husband is 55 and has just been diagnosed with diverticulitis--fairly straightforward, no one seems in any doubt of that. But during the visit to our doctor, the doctor found an enlarged right supraclavicular lymph node. He said to my husband, "This is of SIGNIFICANT CONCERN...but I'm only saying "significant" to get you to take this seriously XXXXXXX So my husband saw an ENT specialist today, who checked his throat and voice box, didn't see anything wrong, but said, "When is your chest X-ray scheduled?" When my husband said, "Wednesday morning XXXXXXX the ENT guy said, "No, call back and get it done TOMORROW XXXXXXX So now my husband's going for the chest X-ray tomorrow. The node is not hard, and it slides around easily--i.e., it's not "stuck" in one place. He has no other symptoms except a persistent cough which he says is a "tickle in his throat"--it's like he coughs to clear his throat and then it's fine; I suspect it's post-nasal drip, and the ENT guy said today that he does have a deviated septum. He has no other chest-related symptoms, no night sweats, no weight loss--nothing that matches with what I have read about lung cancer. His bloodwork looked fine except for a White Blood Count of 17,000, but our doctor said that's typical with the diverticulitis, about which no one seems to have any doubt. Cancer is very prevalent in my husband's family, though, so I'm sitting here thinking, "How scared should we be?" Other than the abdominal issues right now, he seems healthy as the proverbial horse. Are the doctors (like our regular doctor and the ENT guy) saying "DO IT NOW" just to get him to take this seriously (which he certainly is), or should I be quaking in my boots (which I am)?