With advancements in histopathological and immunohistochemical studies, healthcare professionals can now achieve definitive diagnoses, moving away from ambiguous terms like “non-Langerhans cell histiocytosis.” CD1a and langerin stand as important criteria for LCH diagnosis and langerin-negative cases in indeterminate cell histiocytosis are of particular interest to the clinician. The gene discussed is CD207; the disease is Langerhans cell histiocytosis.