Figure 8: Borderline/atypical proliferative/low malignant potential mucinous tumor with microinvasion. A small focus of infiltrative glands with moderate to marked nuclear atypia is present within the stroma underlying a cystic gland. The remainder of the tumor (not illustrated) was a borderline tumor with intraepithelial carcinoma. Microinvasive tumor with this higher-grade appearance might be considered microinvasive carcinoma by some pathologists. Submitted by Brigitte Ronnett, MD