Distinct Histopathologic Features of Complicated Sinusitis. (February 2022) - Brown, Hannah J.
Background: Sinusitis complicated by intracranial or orbital extension can be life-threatening and require emergent intervention. Histologic features of complicated sinusitis have yet to be determined and may have significant implications for understanding pathophysiology. Methods: A structured histopathology report was utilized to analyze sinus tissue extracted during functional endoscopic sinus surgery (FESS). A total of 13 histopathology variables were compared between patients with complicated sinusitis (CS), CRS without nasal polyps (CRSsNP), and CRS with nasal polyps (CRSwNP). Results: About 24 CS, 149 uncomplicated CRSsNP, and 191 uncomplicated CRSwNP patients were analyzed. Nasal tissue from CS and CRSwNP patients demonstrated similar levels of overall inflammation (66.7% vs. 69.6% with moderate/severe inflammation, P = .466 ). Relative to CRSsNP, CS patients showed significantly greater overall inflammation (66.7% vs. 41.6%, P = .019 ). CS patients demonstrated significantly fewer eosinophils per high power field (eos/HPF) and eosinophil aggregates compared to CRSwNP patients (20.8% vs. 70.7% with 5+eos/HPF, P < .0001 ; 4.2% vs. 33.5%, P < .0001 ). Relative to CRSsNP patients, CS patients demonstrated enhanced neutrophil infiltration (45.8% vs. 28.0%, P = .011 ). About 91.7% of CS patients demonstrated a lymphoplasmacytic predominant inflammatory infiltrate, compared to 69.8% of CRSsNP and 62.8% of CRSwNP patients ( P < .0001 ). Conclusion: Significant histopathological differences were evident in patients with CS, CRSsNP, and CRSwNP. CS patients did not perfectly fit either a CRSsNP or CRSwNP profile, underscoring the importance of delineating the histopathological features of CS. This study offers insight into the histologic aspects of CS, providing initial evidence that it is an aggressive neutrophilic inflammatory process.