Table 1: Comparing IP to other Schneiderian papilloma.

PapillomaFungiformInverted Oncocytic Schneiderian

Former name/synonymsSeptal RingertzCylindrical, columnar

Prevalence %50473–5

OriginNasal septumLateral nasal wall and paranasal sinusesLateral nasal wall and paranasal sinuses

Epithelium
pattern of growth
Everted, exophyticInfolded, endophytic

MicroscopyThick squamous epithelium and, less frequently, respiratory epithelium arranged in papillary frondsThickened squamous epithelium admixed with mucocytes and intraepithelial mucous cystsMultilayered epithelium with an eosinophilic cytoplasm among which intraepithelial mucin cysts

Age groupYounger 50~6030~80

Malignancy35% have invasive squamous cell carcinomaLocally aggressive, extending into the sinuses, the orbit, nasopharynx [20], or meninges. Three to 24% (mean 13%) may have an invasive focus of squamous cell carcinoma14%~19%
Malignant change potential

25% multifocalMixed with typical inverted papilloma