A 25-year-old man presents with a two-year history of a single, large, hypopigmented patch that extends from his left thigh up to his knee. There is no associated pain or itching; nor is there a history of trauma or chemical exposure to the affected area. He migrated from Brazil to the United States four years ago. There is no recent history of foreign travel. His medical history is unremarkable. He has a single stable sexual partner.