<s>[INST] I am due an ultrasound on my right arm, there is a large swelling on the top of my forearm with multiple lumps underneath, the lumps started a year ago but the swelling is a recent development  there is pain but my consultant said he has no idea what it is. [/INST] Hi, dearI have gone through your question. I can understand your concern. You may have some soft tissue tumor like lipoma, neurofibroma or dermatofibroma.  Or you may have some benign cyst like ganglion or other cyst. You should go for ultrasound study and if needed go for biopsy.  It will give you exact diagnosis. Then you should take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health. </s>