<s>[INST] Hi I have found a hard, non-movable lump underneath left-side of collarbone. I believe it s the infraclavicular lymph node that is swollen and hardened. I ve done some very preliminary research but wanted to inquire as to the possible causes other than lymphoma or breast cancer. Thank you very much for your time and attention. [/INST] Welcome to Chat Doctor .1. No, breast cancer will not be seen in supra curricular region generally.2. I would think in terms of lipomas initially - if there are no primary pathologies known to.3. If any primary pathology is there then I would think of a lymph nodal mass.4. In any case an ultrasound scan would figure out the content of the lesion and the extensions and involvement of adjacent structures. Anything to ask ? Do not hesitate. Thank you. </s>