Type of Preparation: ThinPrep/ LBP Magnification: Medium Clinical History: Elderly woman with history of hysterectomy and radiation treatment Interpretation: NILM: Rectovaginal fistula Cytomorphologic Criteria: Groups of columnar cells with glandular formation and prominent purple mucin. Background shows granular debris and blood. Explanatory Notes: Orderly arrangement of cells helps differentiate groups from adenocarcinoma. The colonic cells originate from fistula.