Touch imprint cytological diagnosis of nodal Langerhans cell histiocytosis. Langerhans cell histiocytosis (LCH) is a rare neoplasm of the mononuclear phagocytic immunoregulatory system of unknown aetiology. Nodal involvement is uncommon. Cytological findings have seldom been described. A case study of LCH, arising in a submandibular node of a 42-year-old female, is reported. Fine needle aspiration smears were highly cellular and composed of a mixed cell population including eosinophils, lymphocytes, neutrophils, and macrophages. Imprint slides from the surgical specimen of the excised node exhibited Langerhans cells with nuclear grooves, leading to a diagnosis suggestive of LCH. Immunohistochemical staining of the node sections with CD1a and S-100 confirmed this diagnosis. In conclusion, cytology may favorably contribute to the diagnosis of LCH.