Clark’s level
Originally described by W.H. Clark in 1966 is based on the depth of infiltration of the melanoma andrefers to the level of invasion of the tumor; it is really difficult to differentiate between Clark Level II and Level III and It is not used on plantar and palmar areas. It is used to predict prognosis in thin melanomas less than 1 mm
Level I: intraepidermal growth with intact basement membrane (melanoma in situ) (no risk to life)
Level II: invasion of the papillary upper dermis (low risk)
Level III: Invasion fills the papillary dermis (great risk of metastasis)
Level IV: tumor involvement of the reticular dermis (very high risk of metastasis)
Level V: invasion of the subcutaneous tissue