Schwannoma of Nasopharynx–A Rare Case with A Complex Presentation

Abstract

Nasopharyngeal tumors are rare, and schwannomas originating from this location are extremely uncommon. Schwannomas are tumors arising from the Schwann cells of peripheral nerve sheath which are neuroectodermal in origin. These are benign, slow growing, well-encapsulated tumors and are mostly seen in the head and neck region. We present a rare case of schwannoma with nasopharynx as its epicenter in an elderly female patient who presented with complaints of hematemesis, bilateral nasal obstruction and stertorous breathing. Diagnostic nasal endoscopy revealed a smooth mucosa covered globular mass occupying bilateral choana. Contrast-enhanced computed tomography of Nose and paranasal sinuses revealed a homogenous mass occupying the entire nasopharynx extending into the nasal and oropharyngeal cavities. The patient underwent Trans-nasal Endoscopic excision under general anesthesia. Nasopharyngeal tumors have a wide range of presentation and a high index of clinical suspicion combined with imaging modalities is required for diagnosis and pre operative planning. Some tumors can cause life-threatening airway obstruction due to delayed presentation and should be managed efficiently and meticulously, with endoscopic excision being a viable approach for cases confined within the nasopharynx.

Introduction

Nasopharyngeal tumors are an uncommon entity. Malignant tumors are more common in nasopharynx than their benign counterparts, the latter being extremely rare [1]. Herein, we report a rare case of benign spindle cell tumor (schwannoma) with nasopharynx as its epicenter. Schwannomas are slow growing, peripheral nerve sheath tumors arising from the Schwann cells. Sino-nasal tract schwannomas account for less than 4% of all schwannomas [2].

Case Report

A 65 year old female patient presented to the emergency department with complaints of vomiting of altered blood with clots and melena for three days. It was associated with bleeding from both sides of the nasal cavity for one day. Each bleeding episode was unprovoked, moderate in quantity and resolved spontaneously. Patient also presented with history of bilateral nasal obstruction which was initially partial and progressed to complete obstruction over two years. There was associated history of snoring and mouth breathing for two years. She also had history of breathing difficulty and noisy breathing which progressively increased within a week of presentation to hospital.

On examination, patient was conscious and oriented with stable vitals. Patient had severe pallor and also developed stertorous breathing within a week of admission. Examination of nose revealed deviated nasal septum to left with clots in bilateral nasal cavity. Oropharyngeal examination revealed a smooth bulge in soft palate with a narrowed oropharyngeal inlet. Diagnostic Nasal endoscopy (DNE) revealed a smooth mucosa covered globular mass occupying bilateral choana.

Contrast Enhanced Computed Tomography (CECT) of nose and paranasal sinuses showed homogenous mildly enhancing mass of size 4.6*3.6 cm occupying entire nasopharynx and extending anteriorly into nasal cavity and inferiorly into oropharynx (Fig. 1). Patient was transfused three packed cells to improve her hemoglobin prior to invasive procedures. Biopsy taken from the mass under local anesthesia revealed uniform appearance of spindle cells and was reported as a benign spindle cell lesion.

Fig. 1.

Shows a contrast enhanced computed tomography of nose and paranasal sinuses axial A and coronal view B in bone window setting showing a homogenous mildly enhancing mass occupying entire nasopharynx and extending anteriorly into nasal cavity and inferiorly into oropharynx

Considering the age of the patient and bleeding tendency of the mass, sinonasal malignancy and nasopharyngeal malignancies were the first differential diagnoses in our mind. Diagnostic Nasal Endoscopy (DNE) revealed a smooth mucosa covered firm globular mass occupying bilateral choana. Imaging studies and absence of cervical lymphadenopathy helped us to narrow down our diagnosis to benign nasopharyngeal tumor as there were no features of erosion and infiltration of surrounding structures.

As the patient had breathing difficulty, patient was taken up for upfront Trans-nasal Endoscopic excision under General Anesthesia (GA) with tracheostomy back up in view of difficult intubation. Patient was intubated using Macintosh video laryngoscope. Intraoperatively, there was a smooth, firm mass occupying bilateral choana and extending anteriorly into right nasal cavity just medial to middle turbinate with stalk attached to nasal septum. Right middle turbinectomy and inferior turbinate reduction was done. Posterior septectomy was done and mass was delineated and freed from surrounding mucosa. Endoscopic excision of the nasopharyngeal mass was done by pushing the mass into oropharynx after releasing its attachment completely from nasal and nasopharyngeal mucosa and was delivered trans-orally.

Pack removal was done on post operative day 2. Post-operative period was uneventful. The patient was discharged in a hemodynamically stable state. In our case, mass was totally excised and no recurrence was observed on post operative follow up.

Discussion

Benign nasopharyngeal tumors are infrequent and pose diagnostic challenges because of its complexity in clinical presentation. Vascular tumours account for more than 50% of benign non-epithelial nasopharyngeal lesions [3]. Congenital anomalies, hematolymphoid, bony and cartilaginous tumours account for the rest [4, 5]. Schwannomas arising from nasopharynx is an extremely uncommon entity and may originate from the autonomic nerves [6]. Herein, we report this case of nasopharyngeal schwannoma because of its rarity and delayed presentation of the patient leading to life threatening airway obstruction.

Nasopharyngeal tumors have a wide range of clinical presentation and a high index of suspicion is required for accurate diagnosis and management. Nasopharyngeal carcinomas commonly present with cervical lymphadenopathy. Benign tumors present with nasal obstruction and epistaxis [1]. In advanced cases, they present with snoring and mouth breathing as the nasopharyngeal inlet is narrowed by the growing tumor [6]. The presentation in our patient was complex with the primary complaint being vomiting of altered blood and clots associated with melena. As the mass was nasopharyngeal in origin, our patient was bleeding posteriorly with subsequent presentation as hematemesis and melena.

Our patient also developed stertor within a week of admission due to delayed presentation of the patient and the tumor descended into oropharynx with subsequent narrowing of its inlet. This clinical situation might warrant the urgent need to establish airway but a tracheostomy was circumvented in our case as we took up the patient for upfront surgery.

Physical characteristics of the mass can be obtained by performing a diagnostic nasal endoscopy. Contrast enhanced Computed Tomography (CECT) or Magnetic Resonance Imaging (MRI) is imperative before proceeding with a biopsy as some tumors may be highly vascular. They also aid in assessing the morphology, size and extent of tumor, which help in pre-operative planning and assessment [1]. Our patient had a homogenous well-demarcated mildly enhancing soft tissue density lesion occupying entire nasopharynx extending anteriorly into right nasal cavity. Some highly vascular tumors may warrant preoperative digital subtraction angiography with embolization before proceeding with an upfront surgery.

External approaches to nasopharynx include transpalatal, mid-facial degloving, trans-maxillary swing, Le Fort I osteotomy, mandibular swing and infra-temporal fossa approaches. They require an external incision and osteotomy, which can increase post-operative morbidity. Endoscopic approach can be opted for in cases which are confined within the limits of nasopharynx and skull base as it offers better visualization and magnification with lesser complications and better post operative outcomes [1].

Our patient was taken up for upfront surgery following imaging as the patient developed stertorous breathing. Endoscopic excision of the nasopharyngeal mass was done under General Anesthesia by releasing its attachments from surrounding mucosa and the tumor was delivered in toto trans-orally. Post-operative histopathological examination revealed spindle shaped cells with hypocellular and hypercellular areas positive for SOX10, suggestive of Schwannoma (Figs. 2, 3).

Fig. 2.

Histopathological examination with Hematoxylin and Eosin stain at 20X magnification revealing hypocellular areas A and hypercellular areas B with spindle cells showing bland nuclear morphology and buckling/waving pattern

Fig. 3.

Immunohistochemistry with SOX10 staining nuclear positivity in tumor cells at 40 × magnification

Gold standard treatment for schwannoma includes complete surgical resection while preserving the nerve roots as much as possible as they are radioresistant tumors [7]. In our case, mass was totally excised and no recurrence was observed on post operative follow up.

Conclusion

Nasopharyngeal tumors have a wide range of presentation and a high index of clinical suspicion combined with imaging modalities is required for diagnosis and pre operative planning. Some tumors on delayed presentation can present with florid symptoms such as life-threatening airway obstruction and should be managed efficiently and meticulously. Pre operative diagnosis of schwannomas are difficult due to non-specific characteristics on imaging studies. Post operative Histology and Immunohistochemistry are essential for confirmation of diagnosis. Trans-nasal endoscopic excision is the treatment of choice for nasopharyngeal schwannomas

Funding

Nil.

Declarations

Conflict of interests

Nil to disclose.