July 2, 2015
A 24-year-old woman with slowly progressive unilateral nasal obstruction, headache, and a polypoidal mass prolapsing through the left nostril
Sinonasal Schwannoma
- Background: Schwannomas are benign tumors of the peripheral nerves sheaths. Sinonasal schwannomas are rare, comprising less than 4% of head and neck schwannomas. They usually arise from the trigeminal and ophthalmic branches of the trigeminal nerve, and infrequently, from autonomic nerves supplying this region.
- Clinical Presentation: Unilateral nasal obstruction is the most common presentation, followed by epistaxis, anosmia and rhinorrea. On nasal endoscopy, lesions appear as smooth, polypoid masses with occasional areas of superficial ulceration.
- Key Diagnostic Features: On CT, sinonasal schwannomas appear as an expansile mass with bone remodeling and thinning, mild enhancement, and intratumoral cystic areas, although the mass may be indistinguishable from other sinonasal masses on the markedly bright T2-weighted signal (unlike sinonasal polyposis and inspissated secretions, which give lower T2 signal), and multiple internal enhancing septa may allow for preoperative diagnosis. Bone losions with intracranial and intraorbital extensions have been reported, but these features are atypical and do not correlate with malignant potential.
- DDx:
- Squamous cell carcinoma
- Adenocarcinoma
- Lymphoma
- Esthesioneuroblastoma
- Meningioma
- Histology: The tumor cells are composed mainly of elongated spindle cells arranged in fascicles without encapsulation and stain positive for S100.
- Treatment: Surgical excision is the treatment of choice, with good prognosis.
