Hypersegmentation of inflammatory cells in Langerhans cell granulomatosis

Langerhans cell granulomatosis (LCG) is characterized by a mixture of Langerhans cells and eosinophils in varying proportions. The characteristic morphology of Langerhans cells have already been described in many articles, but little attention has been paid to inflammatory cells. We examined six cases of Langerhans cell granulomatosis, which had originally been diagnosed as eosinophilic granuloma. Inflammatory cells present in LCG showed hypersegmentation. Twenty percent to 70% of eosinophils had three or more segmented nuclei, and 10-25% of neutrophils had five or more segmented nuclei. Such findings have never been described, and we believe hypersegmentation to be a feature of LCG. Furthermore, we emphasize that eosinophils in LCG mimic neutrophils in ethanol-fixed preparations, and thus may be a pitfall in making a diagnosis in cytology and intraoperative consultation.