Histopathologic parameters as predictors of early disease recurrence in chronic rhinosinusitis with nasal polyps after functional endoscopic sinus surgery: a prospective cohort study

Background Chronic rhinosinusitis with nasal polyps (CRSwNP) carries a high risk of recurrence despite optimal surgical treatment. Functional endoscopic sinus surgery (FESS) remains the standard of care for refractory disease, but reliable predictors of postoperative recurrence are lacking. Objective To evaluate histopathological parameters, together with relevant clinical and radiological variables, as predictors of early disease recurrence following FESS in patients with CRSwNP. Methods In this prospective observational cohort study, 112 patients with CRSwNP underwent FESS after failure of medical therapy. Preoperative Lund–Mackay CT score and SNOT-22 score were recorded. Excised polyp specimens were assessed for epithelial hyperplasia, squamous metaplasia, basement membrane thickening, subepithelial oedema, fibrosis, glandular hyperplasia, and tissue eosinophil and lymphocyte counts. Patients were followed endoscopically at 3, 6 and 12 months; early recurrence was defined as endoscopic evidence of polyp regrowth within the first postoperative year. Results Early recurrence occurred in 36 of 112 patients (32.1%). Recurrence rates were significantly higher among patients with basement membrane thickening (74.3% vs. 13.0% without, P < 0.0001), fibrosis (46.2% vs. 20.0%, P = 0.003), glandular hyperplasia (40.3% vs. 14.3%, P = 0.006), and comorbid asthma (93.8% vs. 21.9%, P < 0.0001). Mean tissue eosinophil counts were higher in patients with recurrence (37.51 ± 9.5/HPF) than without (32.4 ± 8.5/HPF, P = 0.005); ROC analysis identified an optimal cut-off of 32.5 eosinophils/HPF, giving 80.6% sensitivity and 55.3% specificity for predicting recurrence. Preoperative Lund–Mackay CT scores were also significantly higher in the recurrence group (17.39 ± 2.33 vs. 16.34 ± 2.64, P = 0.04). Epithelial hyperplasia, metaplasia, oedema, tissue lymphocyte counts, and SNOT-22 scores were not significantly associated with recurrence. Conclusion Nearly one-third of patients with CRSwNP experienced early recurrence after FESS. Histopathological features of mucosal remodelling—basement membrane thickening, fibrosis and glandular hyperplasia—together with tissue eosinophilia, comorbid asthma, and higher preoperative Lund–Mackay CT scores were significantly associated with early recurrence in this cohort. These findings support a multifactorial approach to postoperative risk stratification, while the eosinophil threshold requires external validation.