Transnasal Endoscopic Resection of Torus Tubarius Pleomorphic Adenoma

Significance Statement

Salivary gland tumors account for <5% of all head and neck neoplasms, with pleomorphic adenoma (PA) being the most common benign tumor. Pleomorphic adenomas mainly occur in the major salivary glands. Pleomorphic adenoma of minor salivary glands of nasopharynx is extremely rare. Only 16 cases of nasopharyngeal PAs have been previously described in the literature. We present the first clinical report of PA arising from torus tubarius treated successfully with transnasal endoscopic resection.

Case Description

Α 68-year-old male patient referred to our Ear, Nose, and Throat Department with a 5-year history of progressive left nasal obstruction. No other symptoms were reported. Endoscopic examination of nasal cavities and nasopharynx demonstrated a smooth, oval mass arising from the left torus tubarius (Figure 1A). The mass was obstructing the left nasal choanae and a part of the right choanae. Otoscopy and neck palpation were normal. Tympanometry revealed a type A tympanogram. Magnetic resonance imaging (MRI) could not be performed due to patient’s claustrophobia. Computed tomography (CT) scan showed a 4.7 cm × 4.2 cm × 3.9 cm, well-defined, lobar mass in the left site of the nasopharynx, which displaced the soft palate (Figure 2).

Figure 1.

A, Endoscopic image of pleomorphic adenoma (red arrows) arising from the left torus tubarius (blue yellows) the left. B, Postoperative image of the tumor.

Figure 2.

Computed tomography (CT) images showing the tumor. A, Sagittal section showing a well-defined mass into the nasopharynx. B, Coronal section showing that the mass arising from the left torus tubarius (yellow arrow).

An endoscopic resection of the tumor under general anesthesia was decided. The tumor was meticulously detached from the left torus tobarius using bipolar diathermy and 0° 4-mm nasal endoscope. The mass was excised en block with its pedicle, to prevent recurrence, via the transnasal route with a Weil-Blaksesley forceps (Figure 1B). The patient was discharged on the second postoperative day. The histopathological diagnosis was PA (Figure 3). No complications were reported during the immediate postoperative period. At 6-month follow-up period assessment, the patient was symptom-free, and there was no evidence of tumor recurrence.

Figure 3.

Histopathological examination showing. A, A pleomorphic adenoma encapsulated by a capsule of connective tissue, covered by the respiratory epithelial tissue (H&E, ×10). B, A biphasic pattern of the tumor, resulting in the admixture of epithelial and myoepithelial elements in a myxoid stroma (H&E, ×20). H&E indicates hematoxylin and eosin.

Discussion

Salivary gland tumors mostly occur in major salivary glands and less in minor salivary glands (10%-15%). The majority of them are benign and approximately 70% are PAs. ¹ Pleomorphic adenomas located in the parotid gland account for about 75%, in the submandibular gland for about 15%, and in the minor salivary glands only for about 10%. ² If the PA originate from minor salivary glands, palate is most common site. Other sites where PAs can develop are upper lip, nasal cavity (mainly the septum), cheek, floor of the mouth, larynx, and trachea. ^{1 -3} Pleomorphic adenoma of nasopharynx is uncommon and especially PA of torus tubarious is extremely rare. Only 16 clinical reports of nasopharyngeal PAs have been described in the literature, but none of them originated exclusively from torus tubarius, as in our patient. ^{1 –14} This is 17th clinical report of nasopharyngeal PA and the first arising from torus tubarius PA in the literature.

The signs and symptoms of PAs in the nasopharynx are nasal obstruction, hearing loss, aural fullness, otalgia, tinnitus, voice change, dysphagia, and epistaxis. ⁴ Differential diagnosis of nasopharyngeal masses with these clinical signs includes angiofibroma, epidermoid cyst, hamartoma, hemangioma, nasopharyngeal carcinoma, lymphoma, nonepithelial tumors, and so on. ³

Endoscopic examination and radiological assessment are almost necessary in order to diagnose nasopharyngeal PA and choose the appropriate surgical treatment. Pleomorphic adenoma of the nose and nasopharynx generally presents as a well-defined lobulated soft tissue mass in the MRI and CT scans. ^{1,3,4,7 -13}

The treatment of choice is the surgical excision of the PA with histologically clear resection margins. Various surgical approaches have been developed such as transpalatal, transmaxillary, transmandibular, and tranpterygoid. ³ These approaches to the nasopharynx may lead to significant postoperative morbidity and complications, such as soft palate paresis, nasal speech, facial deformity, dental malocclusion, disruption of the nasal skeleton, and Eustachian tube dysfunction. The vast majority of the previous-reported nasopharyngeal PA were treated with transanal endoscopic approaches, sometimes combined with transoral access. Therefore, the gold standard of surgical approach is the endoscopic transnasal approach because it offers less morbidities and better visualization of the surgical field.