What are the dermatological treatments for dark spots/hyperpigmentation on legs?

Surgical biopsy: Most Dermatologist realize skin creams and bleaches from caustic Chemicals are not good for the skin or your health. If a spot appears suspicious (large, growing, irregular in shape, mottled in appearance, bloody) then a biopsy to exclude melanoma or other cancer is indictated. If it is small, circular, and looks the same year after year, leaving it alone & wearing sunscreen is your best bet.