Discusses a case of a biphasic pulmonary blastoma (BPB) with emphasis on expression of the stem cell factor receptor KIT (CD117). Case of a 61-year-old male patient with a BPB of the upper right lobe; Immunohistochemical analysis using a panel of several antibodies including anti-CD117; Strong cytoplasmic expression of CD117 in the epithelium and spindle cells.