Small intestinal adenocarcinoma with microsatellite instability-high (case 36). A: The tumor produced abundant mucin (HE stain, × 20); B: The tumor focally showed signet ring-like carcinoma cells (HE stain, × 200); C: The carcinomatous gland was composed of columnar cells with intracytoplasmic mucin (HE stain, × 200); D: These glands were positive for MUC2 (MUC2, × 200); E: positive for MUC5AC (MUC5AC, × 200); F: But negative for MUC6 (MUC6, × 200). In these microsatellites, the tumor was unstable. Microsatellite analysis of paired normal and tumor DNA using G: BAT25; H: BAT26; I: D17S250.