Figures 1 and 2: Borderline/atypical proliferative/low malignant potential mucinous tumor, gastrointestinal type. Mucinous epithelium exhibits tufts and intraglandular papillary growth without stromal invasion (1) and displays mild nuclear atypia with goblet cells in the differentiated portions of the epithelial tufts (2). Submitted by Brigitte Ronnett, MD