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Sinonasal tumours: inverted papilloma and malignancy

Any one-sided nasal mass or polyp in an adult — especially with bleeding, cheek numbness, proptosis or loose teeth — requires biopsy and imaging; inverted papilloma is the common benign tumour that can turn malignant, and malignant tumours are found late and treated with surgery and radiotherapy.

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Why it matters in the exam

Inverted papilloma usually arises from the lateral nasal wall, one-sided, with bony thickening at the attachment site on CT and a "convoluted cerebriform" pattern on MRI. In about 5% to 10% a squamous cell carcinoma accompanies it. It tends to recur, so it is removed completely including the attachment site — now mainly endoscopically (such as medial maxillectomy), with long follow-up. Krouse staging describes its extent.

The commonest malignant tumour is squamous cell carcinoma, mainly in the maxillary sinus. Adenocarcinoma (intestinal type) appears in the ethmoid sinus and is linked to occupational exposure to wood and leather dust. Other types: adenoid cystic carcinoma (perineural spread), mucosal melanoma, olfactory neuroblastoma (esthesioneuroblastoma — from the nasal roof, spreading through the cribriform plate; Kadish staging), SNUC, and NK/T-cell lymphoma, nasal type (EBV, midline destruction). Symptoms come late: one-sided obstruction, bleeding, cheek numbness (nerve V2), diplopia, proptosis, epiphora and loose teeth.

Ohngren line — an imaginary line joining the medial canthus and the mandibular angle — divides the maxillary sinus: tumours above and behind the line lie near the orbit and skull base and have a worse prognosis. Work-up: endoscopy and biopsy, CT to assess bone and MRI to separate tumour from secretions and to assess the orbit and brain. Treatment: surgical resection (endoscopic or open, including maxillectomy or a craniofacial approach) and adjuvant radiotherapy; orbital exenteration is considered when the tumour invades orbital fat, the muscles or the orbital apex. Lymphoma is treated with chemotherapy and radiotherapy, not resection.

Key points

• One-sided in the nose — biopsy and imaging.
• Inverted papilloma: 5% to 10% carcinoma, complete excision.
• Squamous cell carcinoma in the maxillary sinus — commonest.
• Wood dust — ethmoid adenocarcinoma.
• Ohngren line: above and behind — worse.

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Sources

• NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers — Ethmoid and Maxillary Sinus Tumors, 2025 — Surgery and adjuvant therapy
• European Position Paper on Endoscopic Management of Tumours of the Nose, Paranasal Sinuses and Skull Base, 2010, updated 2023 — Histology-specific management
• Krouse JH. Development of a staging system for inverted papilloma, 2000 — Staging

Sources are given for further reading; the text is written afresh and not copied from them.

Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.