HI,Good Evening.Thanks for your query.I studied the query in-depth.Its the sheer fear of mothers
melanoma, which has made you panicky.I understand your concerns.
I need to have more info-which I can get after clinical examn only.With whatever facts told in your query,I would try to give most probable causes to help you to reduce your worry and to plan treatment with your plastic surgeon before
biopsy.
-Your
dermatologist has asked for a biopsy,means there is no melanoma factor / or the skin factor -involved in your lump and its mostly of subcutaneous lump and you should relax on that positive grounds.
-Mostly in my opinion-Lipoma/ fibromyoma-as lump is painless.
-Excision Biopsy-would fix the differrentiation of the causes of the tricep lump.
-You need not worry of the outcome as both these tumours are benign.
-Hope this would help in discussing with your plastic surgeon.
-Wishing you early recovery and good health.