Papular Lesions on Knees. What is Their Diagnosis?

Giant Juvenile Xanthogranuloma presents as papular lesions with well-defined borders, a yellowish color, and is asymptomatic. These lesions, which began to appear at the age of two, have increased in size and number on the knees. Diagnosis is based on clinical characteristics and is confirmed histologically. Histologically, dermal lesions display a dense linfohistiocytic infiltrate and multinucleated Touton-type giant cells. An interdisciplinary approach is required for study and treatment, with periodic follow-ups. The prognosis is benign, as the lesions tend to disappear over time, but extracutaneous manifestations or associations with systemic diseases should be considered.