Histopathology in Chronic Rhinosinusitis Varies With Sinus Culture.

Background Structured histopathology reporting facilitates better understanding of the underlying pathophysiologic mechanisms of chronic rhinosinusitis. The microbiology of chronic rhinosinusitis has been studied extensively; however, distinct histopathologic changes associated with bacteria isolated in chronic rhinosinusitis are largely unknown. Objective The goal of this study is to better understand the relationship between culturable bacteria and histopathology in chronic rhinosinusitis. Methods A structured histopathology report was utilized to analyze sinus tissue removed during functional endoscopic sinus surgery in a group of patients with chronic rhinosinusitis refractory to medical therapy. Patients with cystic fibrosis or ciliary dysfunction were excluded. Histology variables included eosinophil count per high-power field, neutrophil infiltrate, basement membrane thickening, subepithelial edema, hyperplastic/papillary changes, mucosal ulceration, squamous metaplasia, fibrosis, fungal elements, Charcot-Leyden crystals, and eosinophil aggregates. Baseline Lund-Mackay score and Sinonasal Outcome Test 22 score were also collected. The association of culture data with the aforementioned variables was assessed. Results A total of 59 chronic rhinosinusitis patients who underwent functional endoscopic sinus surgery were included. Chronic rhinosinusitis patients with Pseudomonas aeruginosa had significantly increased neutrophil infiltrate (71.4% vs. 26.9%, p = 0.048), subepithelial edema (28.6% vs. 3.8%, p = 0.047), and a trend toward increased fungal elements (28.6% vs. 5.8%, p = 0.071). Chronic rhinosinusitis patients with Staphylococcus aureus had significantly more hyperplastic changes (20% vs. 2.3%, p = 0.050) and a trend toward increased squamous metaplasia (33.3% vs. 14.2%, p = 0.069). Conclusion Distinct histopathologic changes were noted based on sinus culture data for S. aureus and P. aeruginosa. These findings may have important implications on the extent of surgical management and prognosis after surgery.