Squamous metaplasia and chronic rhinosinusitis: a clinicopathological study.

Background: The significance of squamous metaplasia (SM) in chronic rhinosinusitis (CRS) is unknown. The objectives of this study were to determine the prevalence of SM in histopathological specimens from patients with CRS and to correlate these histological findings with clinical features.

Methods: We reviewed the clinical records and pathological slides from 87 consecutive patients who underwent endoscopic sinus surgery for CRS. Demographic and clinical data, preoperative Chronic Sinusitis Survey (CSS) scores, and sinus CT stage were evaluated. Pathological slides were graded by a pathologist to characterize the degree of inflammation and SM, when present. CRS patients with and without SM were compared using student's t-test and chi2 test.

Results: Evaluation of the pathology slides revealed that 18.4% of specimens had SM present, whereas only 2.2% of pathology reports noted this. Histological grading of chronic inflammation showed significantly greater severity in specimens with SM (n = 16) when compared with the cohort without SM (n = 75; 100.0% versus 77.5%, respectively; p = 0.016). There was no difference in preoperative CT stage or the presence of hyperostosis on imaging, CSS scores, duration of CRS symptoms, or other clinical features between those with SM and those without SM (p > 0.05). Immunodeficiency was the only comorbidity more prevalent in the metaplastic group (12.5% versus 0%, respectively; p = 0.003).

Conclusion: SM is present in approximately 18% of routine CRS specimens. It has a positive correlation with the severity of inflammation noted histologically in CRS but does not correlate with disease severity or chronicity, clinically.