A 4-day-old female baby,who was born naturally, hada2cmrednodule with surface ulcer on her back at birth. Microscopically, the nodule was composed of histiocyte-like tumor cells with a coffee bean-like nucleus that was narrow in the middle. The cells had invaded the whole dermis and were surrounded by eosinophils. They expressed S-100, CD1a and Langerin. We made a diagnosis of Langerhans Cell Histiocytosis (LCH). The biochemical test results were within normal range. Nevertheless, X-ray, echography, bone scintigraphy and brain MRI detected no lesions of the suspected LCH. Based on the clinical symptoms and the pathological and immunopathological features, we suspected a diagnosis of Solitary Langerhans Cell Histiocytosis (Congenital Self Healing Reticulohistiocytosis) in LCH. We followed the patient with no treatment. The nodule disappeared at 31 days after birth. Therefore, we diagnosed her as Solitary Langerhans Cell Histiocytosis (Congenital Self Healing Reticulohistiocytosis). She has had no relapse and her general condition is good at 6 months after birth. However, other reports have described rare relapses in other organs after the regression of skin lesions had been confirmed. As for prognosis, we conclude that careful observation over a long period of time will be required in this case.