Schneiderian papilloma

Definition

These are benign neoplasms of the sinonasal mucosa. They fall into three groups:

exophytic or fungiform papillomas: this type accounts for about 50% of the total2. They most commonly involve the anterior nasal septum. They may contain HPV 6 or 11.
inverted papillomas: this type usually occurs on the lateral nasal wall or middle meatus and may extend into paranasal sinuses. They may contain HPV 6 or 11 and possibly with EBV.
oncocytic or cylindrical papillomas: not associated with HPV .

Clinical features

They are seen across a wide age range, but are most common between the ages of 30 and 60 years. Males are more often affected than females.

Macroscopic appearances

Histopathology

Exophytic papilloma: There is an exophytic architecture, with thick non-keratinising squamous ("transitional") epithelium covering fibrovascular cores. Large glycogenated squamous cells are not a feature. A granular layer and keratinisation, inflammation, atypia and mitoses are uncommon.
Inverted papilloma: the growth pattern is endophytic with imaginations of the epithelium into the stroma. There is a thickened non-keratinising epithelium with a prominent basement membrane. A layer of ciliated columnar cells may cover the surface. Frequently, there are numerous mucous cells and mucous cysts. Large clear cells contain abundant glycogen. Mitoses are usually sparse and limited to the basal layer. There may be a chronic inflammatory cell infiltrate.
Oncocytic papilloma: show the same anatomic distribution s inverted papillomas. The architecture may be exophytic or endophytic. The multilayered epithelial cells have eosinophilic granular cytoplasm. Mucous cells with intra-epithelial mucous cysts contain neutrophils.

Immunohistochemistry

Ultrastructure

Differential diagnosis

Inflammatory polyps: usually bilateral, contain eosinophils and lack marked epithelial proliferation but do contain hyperplastic seromucinous glands.
Oncocytic papilloma with mucous cysts: rhinosporidiosis. However, the epithelium of rhinosporidiosis is not oncocytic and micro-organisms are visible in the stroma.
Low-grade sinonasal papillary adenocarcinoma
squamous cell carcinoma

Management

Prognosis

Multiple recurrences are common, unless extensive resection is performed. Carcinomatous transformation may occur in inverted and oncocytic papillomas, most commonly to squamous cell but less often clear cell, sarcomatoid or mucoepidermoid carcinoma, carcinoma with endodermal sinus tumour-like features, small cell carcinoma or undifferentiated sinonasal carcinoma.

References

1Perez-Ordonex B. Special tumours of the head and neck. Current Diagnostic Pathology 2003;9:366-383.

2Hyams, V. J. (1971). "Papillomas of the nasal cavity and paranasal sinuses. A clinicopathological study of 315 cases." Ann Otol Rhinol Laryngol 80(2): 192-206.

This page last revised 8.2.2004.