We present a case of Langerhans cell histiocytosis (LCH) involving the cranial bone in a 13-year-old boy. Imprint smear cytology showed polygonal cells having relatively abundant cytoplasm with pseudopodial-like projections and convoluted nuclei in a background of eosinophils and small lymphocytes. Immunocytochemical analyses demonstrated positive staining results for CD1a and langerin. Accordingly, a cytological diagnosis of LCH was made. The presence of pseudopodial-like projections in the Langerhans cells may have hitherto been under-recognized. This cytologic feature is considered to be a characteristic finding of LCH in addition to the characteristic nuclear features.