Residency · Residency · Otolaryngology
Sinonasal Tumors: Inverted Papilloma and Malignancy
Overview
Sinonasal tumors encompass a diverse group of benign and malignant neoplasms. Inverted papilloma is the most clinically significant benign tumor due to its tendency for recurrence and association with malignancy. Sinonasal malignancies are rare but aggressive, requiring multidisciplinary management. Endoscopic approaches have expanded the surgical repertoire but open approaches remain necessary for advanced disease.
Inverted Papilloma (Schneiderian Papilloma, Inverted Type)
Epidemiology
Most common benign sinonasal neoplasm requiring surgical intervention. Male predominance (3-5:1); peak 5th-6th decade. HPV association described (types 6, 11, 16, 18) but not consistently demonstrated. Unilateral in >95% of cases.
Pathology
Arises from Schneiderian (ectodermal) mucosa lining the nasal cavity and sinuses. Endophytic growth pattern: epithelium inverts into the underlying stroma (contrasts with exophytic papilloma). Three types of Schneiderian papilloma: Inverted papilloma (most common; lateral nasal wall): endophytic, locally aggressive. Exophytic (fungiform) papilloma: septal origin; true papillomatous growth; low recurrence. Oncocytic papilloma: rare; from oncocytic columnar cells; lateral wall or sinuses.
Clinical Presentation
Unilateral nasal obstruction (most common), Unilateral rhinorrhea or epistaxis, Anosmia, facial pain (advanced). Unilateral nasal polyp in a middle-aged male = inverted papilloma until proven otherwise.
Imaging
CT: unilateral soft tissue mass, often centered at the middle meatus/ostiomeatal complex. Focal hyperostosis at the site of attachment (important for surgical planning). Bony remodeling and expansion; erosion in advanced cases. Calcification pattern may be present. MRI: characteristic cerebriform/convoluted enhancement pattern on T1 post-contrast. Helps differentiate from retained secretions and tumor extent. Useful for assessing skull base and orbital involvement.
Staging (Krouse Classification)
| Stage | Extent |
|---|---|
| T1 | Limited to nasal cavity; no sinus extension |
| T2 | Ostiomeatal complex, ethmoid sinuses, and/or medial maxillary sinus |
| T3 | Lateral/inferior/superior/anterior/posterior maxillary walls; frontal or sphenoid sinus |
| T4 | Beyond sinonasal cavities (orbit, intracranial, pterygomaxillary) or associated malignancy |
T1: tumor limited to nasal cavity; no extension to sinuses. T2: tumor involving ostiomeatal complex, ethmoid sinuses, and/or medial maxillary sinus. T3: tumor involving lateral, inferior, superior, anterior, or posterior maxillary sinus walls, or extension to frontal or sphenoid sinus. T4: tumor extending beyond the sinonasal cavities (orbit, intracranial, pterygomaxillary space) or associated malignancy.
Management
Surgery is the treatment of choice: complete excision with identification and removal of the attachment site. Endoscopic approach: standard for T1-T3 tumors at most centers. Endoscopic medial maxillectomy for lateral wall attachment. Wide exposure of attachment site with subperiosteal dissection. Drilling of the bone at the attachment site (ensure complete removal). Open approaches (lateral rhinotomy, midfacial degloving, Caldwell-Luc): reserved for extensive T3-T4 or revision cases. NO role for radiation therapy in benign inverted papilloma.
Recurrence and Malignant Transformation
Recurrence rate: 5-15% with endoscopic approaches (lower than historical open approaches). Most recurrences within 2-3 years; long-term follow-up required (at least 5 years). Malignant transformation: 5-15% (associated squamous cell carcinoma). SCC may be synchronous (at time of diagnosis) or metachronous (develops later). Complete pathologic review of the specimen is essential to rule out malignancy.
Sinonasal Squamous Cell Carcinoma
Epidemiology
Most common sinonasal malignancy (overall), Peak 6th-7th decade; male predominance. Risk factors: occupational exposure (wood dust, nickel, leather tanning, formaldehyde), smoking, inverted papilloma, HPV (some cases).
Presentation
Unilateral nasal obstruction, epistaxis, facial pain, Facial swelling, epiphora, proptosis (orbital involvement), Cranial nerve deficits (advanced), Often advanced at presentation due to late symptoms.
Staging (AJCC 8th Edition -- Nasal Cavity and Ethmoid)
T1: restricted to one subsite. T2: two subsites or adjacent nasoethmoidal region. T3: medial orbital wall/floor, maxillary sinus, palate, cribriform plate. T4a: anterior orbital contents, skin of nose/cheek, pterygoid plates, frontal/sphenoid sinuses, minimal cribriform invasion. T4b: orbital apex, dura, brain, middle cranial fossa, cranial nerves (other than V2), nasopharynx, clivus.
Management
Early stage (T1-T2): endoscopic resection with clear margins +/- adjuvant radiation. Advanced stage (T3-T4a): open craniofacial resection or endoscopic-assisted resection + adjuvant radiation +/- chemotherapy. T4b: often unresectable; primary chemoradiation or palliative care. Neck dissection: not routinely performed (nodal metastasis uncommon ~10-15%); indicated if clinical or radiographic nodal disease. 5-year survival: ~50-60% overall; worse for higher T-stage.
Esthesioneuroblastoma (Olfactory Neuroblastoma)
Pathology
Arises from olfactory neuroepithelium at the cribriform plate. Bimodal age distribution: 2nd and 6th decades. Hyams histopathologic grading (I-IV): low grade (I-II) vs. high grade (III-IV).
Staging (Kadish, modified)
| Stage | Extent | 5-Year Survival |
|---|---|---|
| A | Confined to nasal cavity | 70-80% |
| B | Extension to paranasal sinuses | 70-80% |
| C | Beyond sinuses (orbit, skull base, intracranial) | ~50% |
| D | Cervical or distant metastasis | <50% |
A: tumor confined to the nasal cavity. B: tumor extending to the paranasal sinuses. C: tumor extending beyond the sinuses (orbit, skull base, intracranial). D: cervical or distant metastasis.
Imaging
CT: mass at the cribriform plate, often extending into the ethmoid sinuses. MRI: dumbbell-shaped mass straddling the cribriform plate; cysts at the brain-tumor interface (Oberman cysts). Calcification within the tumor is common.
Management
Surgery + adjuvant radiation is standard. Endoscopic resection increasingly used for Kadish A-B with equivalent oncologic outcomes to craniofacial resection. Craniofacial resection for Kadish C with intracranial extension. Neck metastasis in 10-20%; elective neck treatment controversial. Chemotherapy: for advanced or recurrent disease (cisplatin/etoposide). 5-year survival: 70-80% (Kadish A-B), 50% (Kadish C).
Sinonasal Undifferentiated Carcinoma (SNUC)
Highly aggressive, poorly differentiated malignancy, Rapid growth; advanced at presentation. Treatment: multimodality (neoadjuvant chemotherapy + surgery + radiation or chemoradiation). Prognosis poor: 5-year survival ~30-40%. Must distinguish from NUT carcinoma (immunohistochemistry for NUT protein).
Other Sinonasal Malignancies
Adenocarcinoma: intestinal type (wood dust exposure) and non-intestinal type; ethmoid sinus predilection. Adenoid cystic carcinoma: perineural invasion hallmark; indolent but relentless course; high rate of late distant metastasis. Mucosal melanoma: poor prognosis; 5-year survival ~20-30%; surgery + radiation; immunotherapy increasingly used for advanced disease. Sinonasal lymphoma: NK/T-cell lymphoma (EBV-associated) in Asian populations; radiation + chemotherapy; diffuse large B-cell lymphoma. NUT carcinoma: defined by NUT gene rearrangement; extremely aggressive; poor prognosis.
<image>Coronal CT and MRI of a left-sided inverted papilloma. CT image shows a unilateral soft tissue mass in the left nasal cavity and ethmoid sinus with focal hyperostosis at the lateral nasal wall (site of tumor attachment). MRI T1 post-contrast shows the characteristic cerebriform (convoluted striped) enhancement pattern of inverted papilloma. Labels indicate the tumor mass, focal hyperostosis, middle turbinate, and intact skull base and orbital walls. The cerebriform pattern on MRI is highlighted with an inset magnification.</image>
<image>Endoscopic surgical photographs showing endoscopic medial maxillectomy for inverted papilloma. Panel A: endoscopic view of a polypoid mass in the right middle meatus. Panel B: uncinectomy and identification of the tumor attachment site on the lateral nasal wall. Panel C: subperiosteal dissection with mucosal cuff around the attachment site. Panel D: drilling of the bone at the attachment site with a diamond burr to ensure complete removal. Panel E: final cavity after tumor removal with clean bony margins.</image>
<image>Sagittal MRI showing esthesioneuroblastoma arising from the cribriform plate with a dumbbell-shaped mass extending from the nasal cavity through the cribriform into the anterior cranial fossa. The intracranial and intranasal components are labeled, along with characteristic peripheral cysts (Oberman cysts) at the tumor-brain interface. The olfactory bulbs, frontal lobes, ethmoid sinuses, and sphenoid sinus are labeled for anatomic orientation. Kadish staging zones (A, B, C) are overlaid on the image.</image>
Clinical Pearls
A unilateral nasal polyp in a middle-aged male is inverted papilloma until proven otherwise -- always biopsy. The site of attachment of an inverted papilloma (identified by focal hyperostosis on CT) must be completely excised and drilled to minimize recurrence. The cerebriform enhancement pattern on MRI is characteristic of inverted papilloma and helps differentiate it from inflammatory polyps or malignancy. Always submit the entire inverted papilloma specimen for pathologic review to rule out synchronous SCC (5-15% association). Esthesioneuroblastoma classically presents as a mass at the cribriform plate with a dumbbell configuration on MRI. Sinonasal malignancies are often advanced at presentation because early symptoms mimic benign sinus disease -- maintain a high index of suspicion for unilateral symptoms. Wood dust and nickel exposure are established risk factors for sinonasal adenocarcinoma and SCC, respectively. Endoscopic approaches are oncologically equivalent to open approaches for select sinonasal tumors but require expertise and careful patient selection.
References
- Krouse JH. "Development of a staging system for inverted papilloma." Laryngoscope. 2000;110(6):965-968.
- Lund VJ, Stammberger H, Nicolai P, et al. "European position paper on endoscopic management of tumours of the nose, paranasal sinuses and skull base." Rhinology. 2010;Suppl 22:1-143.
- Dulguerov P, Allal AS, Calcaterra TC. "Esthesioneuroblastoma: a meta-analysis and review." Lancet Oncol. 2001;2(11):683-690.
- Nicolai P, Battaglia P, Bignami M, et al. "Endoscopic surgery for malignant tumors of the sinonasal tract and adjacent skull base." Arch Otolaryngol Head Neck Surg. 2008;134(11):1166-1172.
