Eosinophilic granuloma of the bone: Cytologic feature of eosinophils

Background: Many studies of the morphology of Langerhans cells in eosinophilic granuloma have been reported, but there have been no reports describing the morphology of eosinophils in detail. Case: A one-year-old female presented with a solid mass in the right pterygopalatine fossa, measuring 4×4×3 cm. H & E-stained imprint cytology specimen revealed Langerhans cell and eosinophils that showed hypersegmentation and indistinct eosinophilic granules. Three and more segmentation was observed in 61% of eosinophils. The lobe index was 2.7. Conclusion: Since eosinophils seen in eosinophilic granuloma show hypersegmentation and indistinct eosinophilic granules, we may mistake them for neutrophils in Papanicolaou-stained smears. When this disease is suspected, Giemsa-stained smears should be used.