Sinonasal tumours

Lesion

Rare nasal and sinus tumours: a bleeding vascular tumour of teenage boys, inverted papillomas, an olfactory neuroendocrine tumour and an aggressive carcinoma.

Updated Nov 12, 2026

Key points

Angiofibroma: adolescent males, recurrent epistaxis; posterolateral nasal wall; many vessels in collagenous stroma; CTNNB1 (β-catenin) mutations, link to FAP; preoperative embolisation.
Sinonasal (Schneiderian) papilloma: inverted (commonest), oncocytic and exophytic; inverted grows downward into stroma, recurs and can transform to SCC.
Olfactory neuroblastoma (esthesioneuroblastoma): roof of nasal cavity near the cribriform plate; nests of small round cells with neurofibrillary stroma, Homer Wright rosettes; synaptophysin, chromogranin, S-100 sustentacular cells.
NUT carcinoma: NUTM1 fusions (often BRD4::NUTM1); poorly differentiated with abrupt keratinisation; most patients survive less than a year.
Small round blue cell differential: lymphoma, small cell carcinoma, Ewing sarcoma, rhabdomyosarcoma, melanoma.

What it is

The nasal cavity and paranasal sinuses host uncommon but characteristic tumours. Sinonasal (nasopharyngeal) angiofibroma is a benign but locally aggressive vascular tumour almost only of adolescent boys. Sinonasal papillomas, especially the inverted type, recur and can turn malignant. Olfactory neuroblastoma is a small round blue cell tumour of the olfactory mucosa, and NUT carcinoma is a rare, very aggressive carcinoma defined by a gene fusion.

Structure

Angiofibroma: unencapsulated mass of thin-walled and staghorn vessels in dense fibrous stroma with stellate fibroblasts.
Inverted papilloma: thick ribbons of transitional-type epithelium with intraepithelial microcysts and neutrophils, growing inward.
Olfactory neuroblastoma: lobules of uniform small cells in fibrovascular stroma, fibrillary matrix, rosettes.
NUT carcinoma: sheets of monotonous undifferentiated cells with abrupt foci of keratin; nuclear NUT staining.

Step by step

In angiofibroma, β-catenin mutations and androgen sensitivity drive stromal and vascular growth in teenage boys.
Papillomas arise from the ciliated Schneiderian mucosa; low-risk HPV or EGFR mutations are found in some.
Olfactory neuroblastoma arises from neuroectodermal cells of the olfactory epithelium.
In NUT carcinoma the fusion protein blocks differentiation and keeps MYC active.

Sinonasal tumours

Tumour	Who	Key feature	Behaviour
Sinonasal angiofibroma	Adolescent males	Vessels in fibrous stroma, CTNNB1	Benign, locally aggressive, bleeds
Inverted sinonasal papilloma	Men 30–60	Endophytic epithelial ribbons	Recurs, may become SCC
Olfactory neuroblastoma	Peak 40s–60s	Small round cells, neuroendocrine markers	Malignant
NUT carcinoma	Any age	NUTM1 fusion	Very aggressive

Markers

β-catenin
Synaptophysin
S-100 sustentacular cells
NUT

Clinical notes

Unilateral nasal obstruction and epistaxis in an adolescent boy suggest angiofibroma: avoid biopsy in clinic because of bleeding.
Unilateral polyp-like mass in an adult needs biopsy to exclude inverted papilloma or cancer.
Olfactory neuroblastoma can cause anosmia and spread into the anterior cranial fossa.

Test yourself

Think of the answer, then tap the question to see it.

Who typically develops a sinonasal angiofibroma and how does it present?

Adolescent males, with nasal obstruction and recurrent epistaxis.

Which sinonasal papilloma is commonest and why is it important?

The inverted papilloma; it grows into the stroma, recurs often and can transform into squamous cell carcinoma.

What genetic event defines NUT carcinoma?

A rearrangement of the NUTM1 gene, most often a BRD4::NUTM1 fusion.

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Connections

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Head and Neck Cancer (MedlinePlus, US National Library of Medicine, 2025).

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