A child is brought by parents with a complain of a solitary well-defined whitish patch on the child's thigh. Which of the following would be the most likely diagnosis?

Nevus achromicus: Presents as hypopigmented macule serrated margins In children Location: trunk, proximal pas of the extremities Histology: Normal or slightly reduced melanocytes. Piebaldism Rare AD disorder of melanocyte development characterized by congenital white forelock and multiple symmetrical hypopigmented or depigmented macules. Albinism AR inheritance Photophobia, vision disorder SCC appear on sun exposed areas of body. Vitiligo Presents at areas under mechanic stress: perioral and periorbital skin, neck, wrists, ankles, dorsum of the hands, breasts etc. Sharply demarcated depigmented macules, merging into larger lesions. Smooth surface, no scales. Usually depigmentation of hairs as well.