Hello - thanks for asking your question.
Of course, nothing is ever 100%. There are certain key characteristics to lipomas that are highly suggestive. The giveaway is that the bulge is soft and depresses when touched. Less likely would be a liposarcoma - which would be cancerous. However it is very rare. If you are still anxious, you could insist on a biopsy which would give you the definitive result.
If the diagnosis is a lipoma, they are typically not treated. If they are in an aesthetically unpleasant location, or it is large enough to cause pain then it can be excised. Options for removal include making an incision and surgically removing it, or liposuction.
If the diagnosis is truly a lipoma it really does depend on you. There is no hard and fast rule to remove them - it is entirely dependent on the patient and surgeon. If you are unsure about the diagnosis, then a biopsy may be considered to confirm what you are dealing with.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.