KIT and platelet-derived growth factor receptor α wild-type gastrointestinal stromal tumor associated with neurofibromatosis type 1: Two case reports

Figure 4 Microscopic and immunohistochemical features (× 200). A: Tumor composed of spindle or polygonal cells with eosinophilic cytoplasm (Hematoxylin-eosin staining); B: Positive for CD117 [3,3’-Diaminobenzidine (DAB) staining]; C: Positive for DOG-1 (DAB staining); D: Positive for CD34 (DAB staining); E: Positive for SDHB (DAB staining); F: Negative for SMA (DAB staining); G: Negative for S-100 (DAB staining); H: Negative for desmin (DAB staining); I: Negative for β-catenin (DAB staining); J: The percentage of Ki67 positive cells was approximately 2% (DAB staining).