Histopathological differences between antrochoanal polyps and chronic rhinosinusitis with nasal polyps in pediatric patients

Background In pediatric patients, nasal polyps primarily manifest as anthrochoanal polyps (ACP) or chronic rhinosinusitis with nasal polyps (CRSwNP). This study compares the histopathological differences between pediatric ACP and CRSwNP, analyzes pathological indicators associated with postoperative recurrence and provides evidence for subtype-specific diagnosis and treatment. Materials and methods This retrospective study analyzed demographic factors, comorbidities and a structured histopathologic report of six variables from 172 pediatric patients (86 with ACP and 86 with CRSwNP) who underwent functional endoscopic sinus surgery. Differences between recurrent and non-recurrent presentations were further examined. Results Mean age in the ACP group was significantly lower than the CRSwNP group ( p =0.007). The CRSwNP group exhibited higher overall severity of inflammation (38.3% v.s. 18.6%, p =0.010). The ACP group showed greater subepithelial edema (65.1% v.s. 37.2%, p <0.001). In the ACP group, the overall degree of inflammation correlated significantly with inflammatory type, and severity of subepithelial edema correlated with collagen deposition. In the CRSwNP group, overall severity of inflammation correlated with eosinophil count per high power field and inflammatory predominance. In the ACP group, the proportion of collagen deposition was significantly lower in recurrent cases (5.6% v.s. 44.1%, p =0.004). In the CRSwNP group, the overall degree of inflammation was significantly higher in recurrent cases (46.7% v.s. 36.6%, p =0.003). Conclusion Pediatric ACP is characterized by prominent subepithelial edema. A lack of collagen deposition indicates a higher risk of recurrence. CRSwNP features severe inflammation, which positively correlates with recurrence.