PMC9900289_01
(a) Coronal CT bone window shows an expansile, polypoid mass in the left nasal cavity. Superiorly, the cribriform plate, olfactory recess and fovea ethmoidalis are eroded and widened (blue arrow). The nasal septum is deviated to the right. The left anterior ethmoid and frontal sinus air cells are opacified. There is convex bulging of the lamina papyracea, which is eroded (orange arrow). The infundibulum and middle meatus are eroded and widened. The left maxillary is opacified. The hard palate is eroded. (b) Coronal CT soft tissue contrast-enhanced image shows a uniformly contrast-enhancing polypoid tumour in the left nasal cavity, extending to the cribriform plate, olfactory recess and ethmoid sinus. No demonstrable intracranial extension. The left maxillary sinus outflow tract is widened and obstructed by a tumour extending into the infundibulum and middle meatus with a resultant effusion (yellow arrow).
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Bulging and demineralisation of the medial wall of the left orbit was present, but no intra-orbital involvement was evident (Figure 1).
(a) Coronal T2 turbo spin echo (TSE) with fat saturation (FS) MRI. There is an expansile T2 solid hyperintense polypoid mass extending intracranially into the anterior cranial fossa with mild mass effect on the inferior left frontal lobe (red arrow). The maxillary sinus is obstructed with a resultant effusion. (b) Sagittal T2 turbo spin echo (TSE) with fat saturation (FS) MRI image shows the antero-posterior extent of the mass, the extradural intracranial component (orange arrow) and obstructed frontal and sphenoid sinuses.
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Superiorly, the mass extended into the left anterior cranial fossa and frontal lobe with mild mass effect but no peritumoural oedema (Figures 2 and 3).
(a) T1 turbo spin echo (TSE) sagittal MR image shows a homogeneously mass, iso-intense to grey matter and muscle (red arrow). (b) Sagittal T1 turbo spin echo (TSE) with fat saturation (FS) with gadolinium-enhanced MR image shows a diffusely heterogeneous enhancing tumour in the left nasal cavity that transgresses the cribriform plate extending intracranially (orange arrow).
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Superiorly, the mass extended into the left anterior cranial fossa and frontal lobe with mild mass effect but no peritumoural oedema (Figures 2 and 3).
(a) Diffusion-weighted imaging B-1000/mm. The mass shows restricted diffusion (red arrow). There is an area of susceptibility artefact anteriorly and at the posterior skull base. (b) Axial ADC map MRI image shows a lobulated left nasal mass with restricted diffusion and small foci of T2 shine-through, ascribed to small foci of intratumoural cysts or necrosis (red arrow).
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There were areas of susceptibility artefact anteriorly and at the posterior skull base (Figure 4). The axial ADC map showed a lobulated left nasal mass with restricted diffusion and small foci of T2 shine-through, ascribed to small foci of intratumoural cysts or necrosis (Figure 4).
Pathological examination showed (a) adenocarcinomatous glands; (b) adjacent primitive neuroepithelium with rosette-like structures; and (c) islands of 'foetal' clear-cell squamous cells. (d) Shows a malignant spindled smooth muscle component with numerous atypical mitotic figures. (e) Proliferation index (ki67) > 70%. (f and g) Immunoreactivity of neuroepithelium with S100 and CD56, respectively, and (h) desmin positivity demonstrating smooth muscle differentiation.
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Microscopic examination revealed fragments of inflamed sinonasal mucosa with foci of atypical glandular structures, composed of pleomorphic cuboidal to columnar epithelium, demonstrating irregular hyperchromatic nuclei and abundant cytoplasm (Figure 5a). Adjacent to the malignant glands, islands of primitive-appearing round-to-oval immature-appearing cells were noted, morphologically reminiscent of olfactory neuroblastoma, representing the neuroepithelial component (Figure 5b). Mitotic figures and rosette-like structures were present, admixed with numerous islands comprising 'foetal' clear squamous cells (Figure 5c). Osseous and cartilaginous differentiation was absent, but sarcomatous areas were evident, composed of fascicles of pleomorphic spindle cells (Figure 5d). The primitive neuroepithelium was positive with S100, CD56 and neuron-specific enolase (NSE) (Figure 5f and g), as well as with neuroendocrine markers, synaptophysin and chromogranin (not shown), while the clear-cell squamous cells were immunoreactive to CD99 (not shown). The spindle cell sarcomatous component was positive for smooth muscle markers, desmin and alpha-smooth muscle actin, representing a leiomyosarcoma (Figure 5d and 5h).