case_images: PMC4095724_01
case_images: Cone beam computed tomography scan showing a sinonasal mass causing opacification of the right maxillary sinus with erosion of the orbital floor, lateral nasal wall, and maxillary sinus floor.
case_images: CRIOT2014-478092.001.jpg
case_images: PMC4095724_01_CRIOT2014-478092.001.jpg
case_images: fig1
case_images: Radiographic evaluation including a computed tomography scan revealed a sinonasal mass causing opacification of the right maxillary sinus with destruction of the lateral nasal wall and maxillary sinus floor (Figure 1).
case_images: Typical histopathological features of the inverted Schneiderian papilloma showing endophytic growth of pseudostratified ciliated epithelium forming cystic spaces (H.E:25x).
case_images: CRIOT2014-478092.002.jpg
case_images: PMC4095724_01_CRIOT2014-478092.002.jpg
case_images: fig2
case_images: Histopathological examination revealed endophytic growth of pseudostratified ciliated epithelium admixed with mucous cells forming cystic spaces into an underlying fibromyxoid stroma with an intact epithelium basement membrane, compatible with inverted Schneiderian papilloma (Figure 2).
case_images: Pseudostratified ciliated epithelium of the Schneiderian mucosa with dysplastic areas (H.E:200x).
case_images: CRIOT2014-478092.003.jpg
case_images: PMC4095724_01_CRIOT2014-478092.003.jpg
case_images: fig3
case_images: At high-power magnification, squamous metaplasia with variables degrees of dysplasia (Figure 3) and areas of invasive squamous cell carcinoma were also found (Figure 4).
case_images: Invasive squamous cell carcinoma showing intense pleomorphism, atypical mitosis, and focal necrosis (H.E:100x).
case_images: CRIOT2014-478092.004.jpg
case_images: PMC4095724_01_CRIOT2014-478092.004.jpg
case_images: fig4
case_images: At high-power magnification, squamous metaplasia with variables degrees of dysplasia (Figure 3) and areas of invasive squamous cell carcinoma were also found (Figure 4).