The skin biopsy revealed infiltration of abundant histiocytes, eosinophils, lymphocytes, and plasma cells, being CD207, CD1a, and S-100 positive by immunohistochemistry. Due to the diversified presentations of Langerhans cell histiocytosis and its propensity to mimic other dermatological conditions, physicians should have a clinical suspicion of this disease and consider it as a differential diagnosis among common skin diseases in pediatric patients. The gene discussed is CD1A; the disease is Langerhans cell histiocytosis.