case_images: PMC8363977_01
case_images: A) axial; B) coronal view of computed tomography showing voluminous spontaneously hyperdense mass taking weak contrast, occupying the ethmoid, maxillary and frontal sinus with bony destruction of the left ethmoidal blade and the roof of the left orbit
case_images: PAMJ-39-78-g001.jpg
case_images: PMC8363977_01_PAMJ-39-78-g001.jpg
case_images: F1
case_images: The mass also invaded the anterior skull base and the conical fat of the orbit with superior rectus muscle causing repression of the left eyeball (Figure 1).
case_images: A) low power showing a proliferation of variably sized nests separated by thick mucoid stroma (H&E x100); B) high power showing tumor cells with plasmacytoid morphology and frequent mitoses (H& E x400)
case_images: PAMJ-39-78-g002.jpg
case_images: PMC8363977_01_PAMJ-39-78-g002.jpg
case_images: F2
case_images: Lymphovascular and perineural invasion was not identified (Figure 2).
case_images: A) immunostaining for cytokeratin AE1/AE3; B) strong and diffuse expression for p16
case_images: PAMJ-39-78-g003.jpg
case_images: PMC8363977_01_PAMJ-39-78-g003.jpg
case_images: F3
case_images: Immunohistochemistry revealed that neoplastic cells were positive for cytokeratin AE1/AE3 (Figure 3) and negative for CK7, CK20, CD117, p40, p63, S100, synaptophysin and chromogranin. P16 showed strong and diffuse immunoreactivity (>70% nuclear and cytoplasmic staining) (Figure 3).