The Association of Serum Eosinophilia with Structured Histopathology in Chronic Rhinosinusitis.

Background: Prior studies have demonstrated associations between serum eosinophilia and chronic rhinosinusitis (CRS) pathogenesis. However, the association of serum eosinophilia with histopathology profiling in CRS has not been fully delineated and may help better characterize CRS disease burden prior to surgery.
Methods: A structured histopathology report of 13 variables was utilized to analyze sinus tissue removed during functional endoscopic sinus surgery (FESS). Complete blood count (CBC) with differential was drawn within 4 weeks prior to FESS. Serum eosinophilia was defined as >6.0% (>0.60 th/μL). Histopathology variables were compared among patients.
Results: A total of 177 CRS patients (37 with serum eosinophilia and 140 with normal serum eosinophilia) were analyzed. Compared to CRS patients with normal serum eosinophil counts, CRS patients with serum eosinophilia demonstrated increased polypoid disease (67.6% vs 35.0%, P  < .001), eosinophil aggregates (45.9% vs 20.7%, P  = .003), and eosinophils per high-power field (>5/HPF) (67.6% vs 40.7%, P  = .003).
Conclusion: CRS patients with serum eosinophilia demonstrated severe disease burden on histopathology with high levels of polypoid disease and tissue eosinophilia. However, a considerable number of patients without serum eosinophilia demonstrated eosinophilic disease on histopathology, indicating that preoperative serum eosinophilia alone could not be reliably used to predict eosinophilic CRS.
Level of Evidence: 4.