METHODS
His laboratory findings were unremarkable. A non-contrast-enhanced
computerized tomography followed by contrast-enhanced computed
tomography scan of the paranasal sinus revealed an ill-defined soft
tissue density lesion measuring 3.2x2.6x2.1cm in the right posterior
ethmoid sinus extending up to the right frontal sinus and nasal cavity
causing erosion of adjacent bones involving right fovea ethmoidalis,
lateral lamella, vertical lamella and middle turbinate with an
indistinct floor of right olfactory groove. Minimal mucosal thickening
is noted in the right maxillary sinus. No definite intracranial or
intraorbital extension was noted.
A preliminary diagnosis of right-sided sinonasal mass was made and the
patient underwent endoscopic sinus surgery. Intraoperative findings
include a friable mass occupying the ethmoid and frontal sinus and
extending up to the nasal cavity and lamina papyracea dehiscence was
also noted. The resected mass was then sent for histopathological
examination. The patient was discharged on the first postoperative day
with no complaints.
Histopathological examination revealed atypical cells arranged in
papillary patterns, sheets, and clusters infiltrating into the fibrotic
stroma. These atypical cells are basaloid and exhibit pleomorphism.
Individual cells have a high nucleo-cytoplasmic ratio, hyperchromatic
nuclei, few visible nucleoli, and a scant amount of cytoplasm.(Figure 1) Mitosis and areas of necrosis were seen. Tumor
tissue was subjected to further immunohistochemistry (IHC) analysis
showed tumor cells positive for CK5/6, EBV, CK, and P40 and negative for
S-100. (Figure2a-2d) INI showed loss of expression.(Figure 3) Based on the overall histomorphological features
combined with the immunohistochemical profile, a final diagnosis of
SMARCB1-deficient sinonasal carcinoma was made.