Atrophoderma of Pasini and Pierini (ATPP) is a rare skin condition that results in patchy areas of discolored skin. The main symptom of Atrophoderma of Pasini and Pierini is multiple irregularly shaped, dark or light areas of skin in which the tissue under the skin breaks down resulting in a depression (dent). The cause of ATPP is unknown. Diagnosis is based on clinical examination and a skin biopsy.