Microvessel barrier dysfunction in sinonasal inverted papilloma‐associated squamous cell carcinoma and its manifestation in dynamic contrast‐enhanced MRI.

Background: To date, an effective means to preoperatively predict the malignant transformation of sinonasal inverted papilloma (SIP) remains lacking due to similarities in clinical appearance. This study aimed to retrospectively evaluate dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) parameters and microvessel structure in tumors with histologically confirmed SIP and inverted papilloma‐associated squamous cell carcinoma (IP‐SCC), as well as correlate DCE‐MRI findings with angiogenesis biomarkers. Methods: Absolute quantitative DCE‐MRI parameters (Ktrans, Kep, Ve) based on the Tofts model and model‐free semi‐quantitative indices (Tpeak, WR, MaxSlope) of SIP (n = 22) and IP‐SCC (n = 20) were investigated. Regions of interest (ROIs) were oriented according to the tumor subsites in the surgical records. Micro‐vessel density (MVD) counts and tight junction protein (claudin‐5) expression were evaluated in tumor specimens obtained during surgery. Differences in the above data were compared between the two groups. Correlations between DCE‐MRI parameters and angiogenic biomarkers were analyzed. Results: Compared with SIP specimens, IP‐SCC specimens were characterized by a significantly higher MVD and a leakier microvessel barrier. The values of Tpeak and Ve were significantly higher for SIP than those for IP‐SCC, whereas WR, MaxSlope, and Kep were significantly lower, indicating early enhancement and a faster dispersion model in IP‐SCC. MVD was positively correlated with WR and Kep and negatively correlated with Tpeak. Tpeak was slightly positively correlated to claudin‐5 expression. Conclusion: DCE‐MRI can serve as a noninvasive biomarker of angiogenesis in the malignant transformation from SIP to IP‐SCC. DCE‐MRI may assist in the differentiation of malignancies and treatment selection. [ABSTRACT FROM AUTHOR]