Type of Preparation: Conventional Magnification: High Clinical History: 71 year old postmenopausal woman Interpretation: HSIL with some features suspicious for invasion Cytomorphologic Criteria: Small squamous cells with irregular hyperchromatic nuclei and high N/C ratios. There is some necrotic cellular debris in the background, which raises the question of possible invasion. Explanatory Notes: HSIL involving endocervical glands may undergo central necrosis when those glands become occluded. In conventional smears, necrotic cellular debris may be seen as focal aggregates of debris (usually associated with abnormal epithelial cells) in an otherwise clean background. This differs from the necrotic debris admixed with broken down blood and inflammation that usually seen in diathesis with invasive lesions. This is an unusual and difficult pattern on Pap tests. Follow-up: HSIL extending into glands with focal epithelial cell necrosis within occluded glands but no invasion