PREVIOUS HISTORY: 4 yrs boy. 20002/12 skin biopsy: Langerhans' cell histiocytosis. 2005/03 BM biopsy: compatible with Langerhans' cell histiocytosis. X-ray: multiple defects in bones, compatible with diagnosis Langerhans' cell histiocytosis (Eo granuloma). Appropriate treatment was applied. 2005/06 spleen and liver biopsies and 2005/09 splenectomy with lymhonodectomy and liver biopsy. Case was consulted by dr.S.Dirnhofer. Diagnosis: Rosai-Dorfman disease like macrophageal reaction, residual LCH infiltration is not excluded. 2 alotransplantations were performed. PATIENT is under CSF therapy.  
BM HISTOLOGY: Cellularity 90%. NASDE+ single elements of granulopoesis and single erythro-islands are present within diffuse infiltration of clear macrophages with single pahogocytosed nuclei (hemophagocytosis?), immature CD34+ cells. A lot of dysplastic small hypolobated CD61+ megakaryocytes (up to 25 HPF) with emperipolesis. There is diffuse I-II reticulin fibrosis, deposition of hemosiderin. A slight infiltration of CD117+ mast cells (single CD1a+/-). S100+, CD1a typical LCH cells are absent.  
PROPOSED DIAGNOSIS 1: Stem cell hyperplasia (CSF associated) and prominent macrophageal reaction with hemophagocytosis. Erythroid hypoplasia and megakaryocytic dysplasia. There are any signs of residual LCH.  
TECHNO QUALITY IS VERY LOW. A LOT OF APPOLOGIES FOR IT.  
PROPOSED FINAL DIAGNOSIS: ACUTE MYELOLEUKAEMIA.