Radiologic Features for Differentiating Sinonasal Inverted Papilloma and Squamous Cell Carcinoma Arising From...

Area of Science:

• Radiology
• Oncology
• Otolaryngology

Background:

• Differentiating sinonasal inverted papilloma (IP) from squamous cell carcinoma arising in IP (IP+SCC) is clinically challenging, especially when computed tomography (CT) shows no bone destruction.
• Accurate differentiation is crucial for appropriate treatment planning and patient management.

Purpose of the Study:

• To identify computed tomography (CT) and magnetic resonance imaging (MRI) features that can distinguish IP from IP+SCC in cases without CT-demonstrated bone destruction.
• To evaluate the diagnostic performance of MRI compared to CT in this specific clinical scenario.

Main Methods:

• Retrospective review of 30 patients with sinonasal IP (n=15) or IP+SCC (n=15) who underwent preoperative CT and MRI.
• Assessment of imaging variables including tumor origin, volume, CT enhancement, T2-weighted and contrast-enhanced T1-weighted signal intensities, apparent diffusion coefficient (ADC), and convoluted cerebriform pattern (CCP).

Main Results:

• No significant differences were found in tumor origin, volume, or CT enhancement patterns between IP and IP+SCC groups.
• IP+SCC more frequently showed intermediate signal intensity on T2-weighted and contrast-enhanced T1-weighted MRI (p=0.025, p=0.029).
• Median ADC values were significantly lower in IP+SCC (0.99×10-3 mm2/s) compared to IP (1.20×10-3 mm2/s) (p=0.026).

Conclusions:

• MRI is more informative than CT for differentiating IP+SCC from IP in sinonasal lesions without CT bone destruction.
• Intermediate signal intensity on specific MRI sequences and lower ADC values are indicators of malignant transformation.
• Tumor size, CT enhancement, and CCP alone are less reliable for distinguishing between IP and IP+SCC.