What causes lump on arm?
Patient: Hi!I have a large painless lump, about the size of a 50 cent piece,  on the bend of my right arm, sitting right at the end of the forearm just below where one would usually extract blood from. I did not notice it until last week and cannot accurately say how long it's been there. The lump is hard and shaped like one half of a very small egg. Doctor: Thanks for your question on HCM. Following are the common causes for lump at elbow joint area. 1. Dermoid 2. Lipoma 3. Fibroid 4. Tenosynovitis (inflammation of tendon sheath) So better to consult doctor and get done 1. Clinical examination of swelling 2.  X ray of elbow joint 3. Ultrasound examination of swelling. X ray is needed for exact location of swelling and whether associated with elbow joint or not. Ultrasound is needed to determine type of swelling and it's content. If it affects elbow joint movement then surgical removal is necessary.