PDGFRA and neoplasm: Mild to moderate nuclear atypia was significantly associated with KIT exon 11 (100%) and exon 9 mutations (100%) whereas 37.5% cases with PDGFRA exon 18 mutation and 15% of wild type GISTs showed severe atypia including plasmacytoid cells and binucleate tumour giant cells (p=0.01) (Figure 2).