Latent class analysis of structured histopathology in prognosticating surgical outcomes of chronic rhinosinusitis with nasal polyps in Singapore

Structured histopathology profiling is recommended when reporting chronic rhinosinusitis with nasal polyp (CRSwNP) tissue. The objective of this study is to identify features in structured histopathology that predict outcome after functional endoscopic sinus surgery (FESS) in a cohort of CRSwNP patients from Singapore.Latent class analysis was performed on structured histopathology reports of 126 CRSwNP patients who had undergone FESS. Outcome measures were polyp recurrence, need for systemic corticosteroids, revision surgery or biologics, and disease control at 2 years post-FESS.Three classes were identified. Class 1 was characterised by mild, predominantly lymphoplasmacytic inflammation. Class 2 comprised of 100 eosinophils/HPF, hyperplastic seromucinous glands, mucosal ulceration and mucin containing eosinophil aggregates and Charcot-Leyden crystals. Classes 2 and 3 were significantly associated with uncontrolled disease at 2 years post-FESS. Class 3 was additionally associated with the need for systemic corticosteroids.Eosinophil count, degree of inflammation, predominant inflammatory type, hyperplastic seromucinous glands, mucosal ulceration and mucin containing eosinophil aggregates and Charcot-Leyden crystals predicted need for systemic corticosteroids and uncontrolled disease at 2 years post-FESS. The presence of >100 eosinophils/HPF should be reported, as this subset of tissue eosinophilia was associated with less favourable outcomes after FESS.