pigmented nevus. big flat benign brown birthmark on man back. close up picture of dangerous brown nevus on human skin -

back benign birthmark black blemish body brown cancer care cell checking clinic close closeup consultation dangerous dark dermatologist dermatology diagnosis disease epidermal examination health human lesion macro male malignant mark medical medicine melanin melanocyte melanoma melanomas mole naevus nevus nodular pigment pigmentation pigmented risk skin spot tag treatment tumor woman