Schwannomas are rare, benign, slow-growing tumors arising from Schwann cells which are responsible for the formation of the myelin sheath. Twenty-five to 45% of tumors arise in the head and neck, of which only 4% were arising from the nasal cavity and paranasal sinuses [6, 7]. Only 20 cases of nasal schwannoma have been reported to date. They occur equally in both genders in the 5th or 6th decade of life. However, in our case, the patient was 32 years of age. The most frequent origin is from the vestibulocochlear nerve . Sinonasal schwannomas arise from branches of the trigeminal nerve (ophthalmic/maxillary divisions), sphenopalatine ganglion, and nerves innervating the nasal mucosa [9, 10]. The lateral wall of the nose is supplied by the anterior ethmoidal nerve, lateral posterior superior, and inferior nasal nerve, so we thought that the origin of the tumor would be from the aforementioned nerves. But it would be difficult to make a definitive statement regarding the nerve involved. Hence, further research is warranted to identify the nerve of origin in nasal schwannomas.
Majority of schwannomas present with unilateral nasal obstruction, pain, headache, epistaxis, and rarely diplopia, proptosis, and ptosis. Habesoglu et al. in their study of 207 patients with complaints of unilateral nasal obstruction reported that 20.6% were neoplastic etiologies. Of neoplastic etiologies, inverted papilloma was the most common pathology and the least common tumors were schwannoma, ameloblastoma, pleomorphic adenoma, non-Hodgkin lymphoma, and squamous cell carcinoma; accounting for only 1.6% .
Generally, nasal schwannoma arises from the middle meatus and in rare cases—the nasal septum [5, 12,13,14] and lateral wall. Only one case of schwannoma arising from the nasal vestibule has been reported to date .
Our patient presented with nasal obstruction, lack of features of facial pain, headache, and facial fullness further pointed to the fact that sinuses were un-involved and the osteomeatal complex was clear. Most of the cases reported bleeding on touch. However, in our case, since it was arising from within the lateral nasal wall, it did not bleed on touch. In a single case reported of a tumor arising from the lateral wall of the nose, the tumor was a pedunculated skin-lined mass. However, in our case, the mass had a broad-based globular appearance. A classic feature of head-and-neck schwannomas is a well-defined capsule, with the exception of tumors of the nose and paranasal sinuses, which have been reported in all prior cases, as being acapsular. Other authors have theorized that the lack of a capsule could be attributed to these tumors deriving from the autonomic nerves of the sinonasal mucosa, which lacks perineural cells. Contrary to the above finding, histopathology in our case revealed a well-encapsulated schwannoma. The tumor was composed of alternating hypercellular and hypocellular areas. Hypercellular (Antoni A) areas show interlacing bundles of the spindle-to-oval cells arranged in a whirling pattern with nuclear palisading forming Verocay bodies.
The treatment of schwannoma is excision. The surgery can be done endoscopically or by an external approach. Since in our case the size of the tumor was such that it was not possible to excise the tumor endoscopically due to the inability to navigate the endoscope further, the tumor was excised by an external approach under general anesthesia. The skin incision was given over the alar crease. The mucosal incision was given over the mucocutaneous junction over the swelling in the nasal vestibule all around the alar rim. Mucosal flaps were raised, and swelling was identified. Dissection was done, and swelling was freed from the surrounding structures. The mucosal layers were sutured using absorbable sutures. The skin closure was done with fine sutures to maintain cosmesis. Recurrences are rare to occur. The patient is doing well on follow-up.