Fig. 1

a Photomicrograph of case 1 (pure ISMC) showing the tumor in the centre (stage pT1), tubular adenoma on right and normal mucosa on either side. (H&E; original magnification × 0.6). b Low power showing the lobulated pushing margin of the tumor to the left and centre. (H&E; original magnification × 2). c The tumor showing a trabecular pattern with peripheral palisading. There are stratified epithelial cells with variable amounts of intracytoplasmic mucin. The stroma shows a lymphoplasmacytic infiltrate (H&E; original magnification × 20). d More detailed cytologic features of the trabeculae. The peripheral cells have round vesicular nuclei and amphophilic cytoplasm (mucin-poor). More mucin-containing cells centrally. (H&E; original magnification × 40)