Cytologic-histologic correlations in the diagnosis of inverted sinonasal papilloma

We present cytologic data from multiple samples from two cases of inverted sinonasal papilloma (ISP). These samples displayed the entire spectrum of squamous cell changes, including benign squamous papilloma, variable degrees of dysplasia, and invasive squamous cell carcinoma. In all instances, the cytologic impression coincided with the final diagnosis based on frozen and/or permanent histologic sections from the same samples. We suggest that cytologic examination be viewed as a useful initial approach in the diagnosis of ISP, and in the differential diagnosis of other tumors that occur in the same sites.