Fig. 1

A 23-year-old male with a metasynchronous mediastinal germ cell tumor and acute myeloid leukemia. a Computed tomography demonstrated an 18-cm anterior mediastinal mass. b Bone marrow aspirate smear examination (4 months after germ cell tumor diagnosis) demonstrated acute erythroid leukemia 70–80 % markedly dysplastic and left-shifted erythroid precursors with myeloid blasts (inset) accounting for more than 20 % of non-erythroid cellularity. c Post-treatment resection of the mediastinal germ cell tumor demonstrated predominantly mature teratoma with focus of rhabdomyosarcoma (pictured) with desmin positivity (inset). d Separate focus of angiosarcoma was also identified in the mediastinal germ cell tumor (pictured), supported by CD31 positivity (inset)