PMC9883109_01
Right nasal cavity mass (star). MT, middle turbinate; S, septum.
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Rigid nasal endoscopy demonstrated tumor along the bilateral septum with what appeared to be potential submucosal spread on the right ( Fig. 1 ). 
Preoperative computed tomography (CT) (
A
) and magnetic resonance imaging (MRI) (
B
-
D
) images of right sinonasal mass with intraorbital extension (star), anterior cranial fossa extension (arrow), and nasolacrimal duct involvement (arrowhead).
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There was thinning of the right fovea ethmoidalis and lateral lamella, with areas of apparent osseous dehiscence and intracranial extension ( Fig. 2 ). There was no involvement of the tissues of the orbit or extraocular muscles, but there was involvement of the nasolacrimal duct ( Fig. 2 ). 
Basaloid pattern with nests of basophilic cells with high nuclear-to-cytoplasmic ratio growing in a desmoplastic stroma.
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 A biopsy was done in clinic and pathology showed a basaloid histologic pattern with nests of basophilic cells with high nuclear-to-cytoplasmic ratio growing in a desmoplastic stroma ( Fig. 3 ).
Immunohistochemistry with a complete loss of SMARCB1(INI-1), which was retained within the normal stromal background cells.
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The tumor cells on immunohistochemistry demonstrated a complete loss of SMARCB1(INI-1), which was retained within the normal stromal background cells ( Fig. 4 ). 