In the case of the 51-year old proposita, the diagnosis of an AML M4eo was confirmed morphologically and cytogenetically by the characteristic inversion (16) (p13q22) in 12/2003. Because of a punctio sicca, no blood from the bone marrow could be aspirated for FACS analysis. A complete remission, also on cytogenetic level, was achieved after the first cycle of cytosine arabinoside, idarubicin, and etoposide induction therapy. This outcome was consolidated by high-dose chemotherapy with cytosine arabinoside and mitoxantrone as well as consecutive allogeneic PBSCT from an HLA-matched sibling donor after total body irradiation/cyclophosphamide (TBI/Cy) in 05/2004. Four weeks after the PBSCT, a 100% donor chimerism was detected. The patient experienced chronic graft versus host disease (GvHD), necessitating a low-dose systemic steroid treatment.
 In 11/2007, a hysterectomy was performed after the occurrence of a painful uterine tumor, yielding the diagnosis of a GS-expressing MPO, the monocyte marker CD68 and KiM1P, without any bone marrow manifestation of the AML (Figure 1). The donor chimerism remains 100%. The surgery was followed by radiotherapy of the pelvis and withdrawal of immunosuppressive medication, leading to limited GvHD with cutaneous and mucocutaneous manifestations.
 In 11/2008, recurrent epigastric pain leads to a gastroscopy documenting again a GS (expression of CD68 and MPO) of the duodenum, without bone marrow infiltration and detectable inversion 16 and still with 100% donor chimerism. The patient received high-dose salvage chemotherapy with cytosine arabinoside and mitoxantrone, followed by donor lymphocyte infusions (DLI) inducing a third complete remission. However, in 04/2009 a meningeosis leukaemia (227 cells/mm3 liquor, expression of CD68 and MPO) was diagnosed, and treatment with intrathecal cytosine arabinoside initiated. The patient received no systemic chemotherapy because of a reduced general state of health and died from meningeal leukemia progression in 03/2010.