Intraoperative diagnosis of osseous eosinophilic granuloma by touch preparation: report of two cases with immunohistochemistry and electron microscopy.

We report two cases of eosinophilic granuloma (Langerhans cell histiocytosis) of bone, the diagnosis of which was made by intraoperative cytological evaluation of touch preparation. The clinical, cytologic, histologic, immunohistochemical, and electron microscopic findings are presented. Our cases demonstrate and further support that intraoperative cytologic analysis by touch preparation is a very useful method of diagnosis during intraoperative consultation on a bony specimen.