Conversation: The conversation between human and AI assistant.
[|Human|] Hi.  Ive had a small moveable lump on the right hand side of my neck since I was about 16.  Im now 31 and wondering if it is something I should get checked out.  My doc at the time had a quick palpation and told me its nothing.  No ultrasound, nothing.  Its about 12mm in diameter and painless.  Ive always assumed its a cyst.  Can these things develop into something nasty over time?  Should I get it checked out again?
[|AI|]  Welcome to Chat Doctor .1. It seems like a brachial cleft cyst - developmental disorder.2. You don't have to worry about it, if it's not causing any mass effect on the adjacent structures.3. But I would recommend you to get an ultrasound neck scan done to evaluate the lesion. (ultrasound helps in finding the nature of the lesion, its source and extensions. 4. Then you can just monitor the lesion without any intervention.5. Another possible cause is vascular structure - malformation. Hope it helps you. Wish you a good health. Anything to ask ? Do not hesitate. Thank you.