Type of Preparation: Conventional Magnification: High Interpretation: Endocervical adenocarcinoma in situ (AIS) Cytomorphologic Criteria: Pseudostratified strip of cells demonstrating nuclear enlargement and crowding and peripheral feathering. Smear background is clean. Explanatory Notes: Pseudostratification, nuclear crowding and feathering are classic features of AIS. Follow-up: Endocervical adenocarcinoma in situ