CRS is a frequently observed condition in patients with immunodeficiency secondary to immunosuppressive medications. CRS’s histologic features among patients undergoing immunosuppressive treatment have yet to be determined and may have important implications for understanding the disease process’s pathophysiology.

A structured histopathology report was utilized to analyze sinus tissue removed during FESS. Histopathology variables, LMS, and sinonasal outcome test 22 scores were compared among patients.

Fifteen CRSi, 36 CRSwNP, and 56 CRSsNP patients undergoing FESS were analyzed. Compared to CRSsNP, CRSi patients exhibited increased moderate-severe inflammation, increased neutrophil infiltrate, and decreased fibrosis. Compared to CRSwNP, CRSi patients demonstrated reduced fibrosis, decreased eosinophil aggregates, and a trend toward fewer eosinophils per high-power field. CRSi cases had significantly lower mean LMS compared to CRSwNP.

The study concluded that CRSi patients exhibit histopathology and disease severity more similar to CRSsNP trends toward increased neutrophilia and reduced fibrosis. In the appropriate clinical context, discontinuing or changing a patient’s immunosuppressive regimen may be a valid treatment option in patients with CRSi. This study provides initial insight into understanding the propensity for chronic sinusitis in patients undergoing immunosuppressive treatment, which may impact disease management.