<s>[INST] Hi, I have a swelling on the left side of my neck...Lower part, a little above the collar bone....I had it around a month back or so but then it went away just like that and now its re-appeared. It is also accompanied by fever for a brief while which then subsides. Could the re-appearance signify malignancy? [/INST] Hi! This is common, very common a presentation of our body immunity fighting against any kind of assault that our lymphoid system faces... Yes, it could be recurrent infection in our throat, nose, teeth, oral cavity, lungs, arms, thyroid, ear and so on... Malignancy? Rarely! But possibility is still there but in that case once the lymph node is enlarged, it goes on enlarging, never reducing or receding...! So in your case you must be happy to learn that some systemic viral infection raised this node and not malignancy; only aged people with other symptoms should be worried about that; only 5% of cases... Therefore, see your doctor today for a detailed examination and possibly a needle biopsy if needed at all!regards, </s>