Lesion Excision

If a patient comes in for an office visit because they have an abnormal lesion can we bill for the lesion excision and an office visit or just the excision?

E/M/procedure

It depends on patient status. Questions asked to determine if you will or will not perform the excision are part of doing the procedure. If a new patient, an E/M is probably medically necessary. If the patient was told to return for the excision, only bill excision code.
If managing other conditions not related to excision, bill E/M and procedure (modifier 25, if minor procedure on E/M code).