my 34 year old son was just told today he has melanoma in situ and that it will be surgically excised within 2 weeks .It was in a mole on his forearm.They said it was stage 1 but barely even that.Is that a good prognosis? Should he have a sentinel node biopsy? CT,MRI or PET scan? He has no illness, does not smoke,drinks socially and is on no medication .He is of 25% Lebanese ,the rest northern European ethnicity. He has had alot of moles for years, has moderate sun exposure.