Lump on left shin in fat layer (had scan) which has been there for 2 months. not sore, not growing, no previous trauma to leg. what could it be?

Lipoma...: Lump which is contender, soft, or firm but on scan no concern . Common is deposits of fatty tissue in subcutaneous layer - it happens without reason. it is benign condition. Sometimes it may be also skin " wax" retired as sebaceous cyst. Either condition is benign and unless anoying - leave it alone. If Any unusual growth, redness, pain .. see your doctor