Fig. 1

a, b The tumor tissue were composed of oval or round mononuclear cells and mixed osteoclast like multinucleated giant cells, with patchy hemorrhage, a few scattered mononuclear cells, and eosinophilic infiltration. c Bone marrow biopsy can be useful in the diagnosis of eosinophilic granuloma (EG). The granulocytic proliferation was active and can be seen in every stage. The erythroid hyperplasia was active, and red blood cell family can be seen. There were many megakaryocytes