Type of Preparation: SurePath/ LBP Magnification: High Interpretation: Squamous cell carcinoma Cytomorphologic Criteria: Highly atypical cluster of cells with loss of polarity, variable N/C ratios, nuclear membrane irregularities (better appreciated by focusing up and down), and prominent nucleoli. Intracytoplasmic nuclear debris and mitosis are also present. Explanatory Notes: Both repair and invasive carcinoma have prominent nucleoli; however the atypia seen in carcinoma, as well as isolated malignant cells and diathesis were useful in making the correct interpretation. The malignant cell clusters show more rounding on liquid preparations and in an individual cell group distinction between a squamous and glandular lesion may be difficult. Attention should be given to looking for isolated dysplastic cells in the background.