Congenital Langerhans cell histiocytosis mimicking a "blueberry muffin baby".

Congenital Langerhans cell histiocytosis (LCH) is a rare condition with great diversity. A case of congenital skin-only LCH presenting as a "blueberry muffin baby" with a spontaneous regression by the age of 8 months is reported here. New insights into clinical manifestations and prognosis, which is not uniformly positive, are discussed. A thorough examination and a careful follow-up should be provided to these patients. Systemic therapy is warranted in multi-system disease; no consensus on treatment exists in case of LCH isolated to skin. The diagnosis of congenital self-healing LCH should be made only retrospectively.