Summary

The report describes the case of a young male with a malignant teratoma which was followed by an acute megakaryoblastic leukaemia sharing similar chromosomal abnormalities. In leukemic cells, the authors have obtained cytogenetic evidence by fluorescent in situ hybridisation technique suggesting that this leukaemia arose directly from the germ cell tumour (GCT). The patient received allogenic bone marrow transplantation, which unfortunately, did not prevent the patient to relapse with an undifferentiated sarcoma containing rhabdomyosarcoma components, as well as reappearance of a residual teratoma with metastasis. The treatment strategy for malignant transformation of a GCT seems to be unpredictable and should be dictated by the malignant tissue counterpart. Except for acute leukaemia, unresectable or metastatic settings will generally require multi-modal therapy including chemotherapy, in addition to loco regional approaches. Additionally, long or even a life time follow-up is necessary in patients with poor prognostic characteristics.