Figure 4

Photomicrographs of the primary omental GIST tumor. A. Epithelioid components of GIST. Tumor cells show eosinophilic cytoplasm and peripherally placed nuclei, and are mostly cohesive (H&E). B. Some components show a spindle cell pattern with myxoid stroma (H&E). C. Tumor cells weakly immunoreactive for c-kit (CD117). D. Immunostaining for MIB-1: sparse of positive tumor cells are shown (MIB-1 index: 4.4%).