Hypopigmented mycosis fungoides (MF) is a rare variant of cutaneous T-cell lymphoma, a type of extranodal non-Hodgkin lymphoma. This report presents the case of a 9-year-old boy with a 2-year history of asymptomatic, hypopigmented skin lesions that were resistant to topical treatment. He was initially treated for a fungal skin infection and had received multiple courses of topical antifungals and steroids but showed no improvement, which led to further evaluation and a referral to a dermatologist. A skin biopsy was performed, and the diagnosis of hypopigmented MF was confirmed through skin histopathology and immunohistochemistry study. His lesions responded well to cycles of narrowband ultraviolet B phototherapy, showing almost complete clearance after 4 months without any side effects.