PMC9678676_01
Computed tomography (CT) scans (soft tissue window). (a) Unenhanced axial CT reveals a lobulated hypodense nasal tumor with no calcification. (b) The coronal contrast-enhanced CT reveals the inhomogeneous well-enhanced tumor with the destruction of skull base and left lamina papyracea with the tumor.
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CT revealed a 49 x 40 x 39 mm lobulated and heterogeneous hypodense tumor (Fig. 1a). Contrast-enhanced CT showed a well-enhanced lobulated tumor with the destruction of the skull base and lamina papyracea (Fig. 1b).
Magnetic resonance imaging (MRI). (a) The main parts of the tumor have high-signal intensity (SI) area with an irregular central low-SI area (arrow) on axial T2-weighted images (T2WIs) (repetition time [TR]/time/effective echo time [TE], 5000/98 ms). (b) Coronal T2WIs also reveal low-SI linear structures corresponding to the septum and fibrous tissue in the tumor. (c) The tumor has mainly an isointense area compared to that of the muscle with a slightly hyperintense central area (arrowhead) on axial T1-weighted images (T1WIs) (TR/TE, 667/10 ms). Homogeneous moderate- and high-intensity areas are observed in the sphenoid sinus on T1WIs, corresponding to mucus retention (arrow). (d) The tumor shows mainly inhomogeneous intense enhancement on axial contrast-enhanced T1WIs. (e) Sagittal contrast-enhanced T1WIs reveal the central area of the tumor with no contrast enhancement (arrowhead), corresponding to hemorrhagic necrosis (TR/TE, 467/10 ms). (f) Diffusion-weighted images show that most parts of the tumor have low and high signal intensities with peripheral high linear signal intensity corresponding to the artifact (TR/TE, 10000/88, b-value = 1000 s/mm2). (g) The mean apparent diffusion coefficient of the tumors was 1.43 x 10-3 mm2/s (b = 1000 s/mm2).
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T2WIs, the tumor mainly had a high-signal intensity (SI) area, with an irregular central low-SI area (Fig. 2a). The tumor also had a low-SI septum and fibrous tissue on T2WIs (Fig. 2b). On T1WIs, the tumor mainly showed iso-SI compared to that of the muscle with a central high-SI area (Fig. 2c). Moderate- and high-intensity areas were observed in the sphenoid sinus on T1WIs, corresponding to mucus retention (Fig. 2c). On contrast-enhanced T1WIs, the tumor showed markedly intense contrast enhancement in the solid parts and septum within the tumor (Fig. 2d). In contrast, the central area showed no contrast enhancement, corresponding to hemorrhagic necrosis within the tumor (Fig. 2e). Diffusion-weighted images showed that the tumor had low- and high-SI areas (Fig. 2f). The apparent diffusion coefficient map of the same region (b = 1000 s/mm2) showed no significant restricted diffusivity (Fig. 2g).
The positron emission tomography (PET/CT). The PET/CT image shows inhomogeneous increased accumulation of 18F-FDG in the tumor. The maximum standardized uptake value for nasal tumor was 3.5.
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PET/CT imaging was performed for further image evaluation and revealed a nasal mass with inhomogeneous increased accumulation of 18F-FDG and no abnormal accumulation in other regions or lymph nodes (Fig. 3).
Histopathological findings of the surgical specimen. (a, b) Microscopically, hematoxylin-eosin staining shows round- and spindle-shaped atypical cells with intratumoral hemorrhage (a: low magnification, b: high magnification; hematoxylin and eosin staining).
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Hyalinization and mucinous stroma were also observed (Fig. 4).