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Case report

An 80-year-old woman presented with hearing loss on the left ear for several years. She was diagnosed with otitis media with effusion (OME) on the left ear at an ENT clinic. Paracentesis of the tympanic membrane was performed, and medications were given. However, the hearing loss was recurrent. Nasopharyngeal endoscopy was conducted, and a tumor was found in the left wall of the nasopharynx. Tumor biopsy revealed pleomorphic adenoma. She was then referred to our hospital.

The nasopharyngeal tumor demonstrated a smooth surface and completely obstructed the orifice of the Eustachian tube. This tumor moved with deglutition, but it always obstructed the orifice of the Eustachian tube ( Fig. 1 A ). An otoscopy showed middle ear effusion in her left ear ( Fig. 1 B). The audiogram showed mixed hearing loss with air–bone gap of 15–40 dB and an impedance audiometry showed B-type. Sonotubometry revealed complete blockage of the Eustachian tube. Computed tomography showed a 21 × 22 mm-sized tumor in the left and posterior wall of the nasopharynx. Middle ear cavity was filled with effusion, but the ossicles and other structures were intact. On magnetic resonance (MR) imaging, the tumor showed low intensity at T1 weighted-image and iso-intensity at T2 weighted-image. This tumor was well enhanced after administration of gadolinium ( Fig. 2 ). From these findings, this tumor originated from the opening of the Eustachian tube or the fossa of Rosenmüller and interfered with tubal function.

The nasopharyngeal tumor totally occluded the orifice of the Eustachian tube (A). The middle ear effusion was observed on her left ear (B).

The tumor was well enhanced after administration of gadolinium. The Eustachian tube was completely blocked by the tumor.

A transnasal endoscopic surgery was done under general anesthesia. Left inferior conchotomy was performed, and a wide surgical view was obtained. The base of the tumor was posterior to the opening of the Eustachian tube. This tumor was carefully retracted inferior by intraorally inserted curved forceps. The mucosa around the tumor was incised by fine-edged monopolar electric cautery (Colorado® microdissection needle, Stryker, USA). This tumor was slightly adherent to the mucosa and cartilage of the Eustachian tube, which caused the tubal dysfunction. The tumor was carefully and totally removed which left a wide mucosal defect. This defect was covered with polyglycolic acid seat (PGA seat; Neovail, Gunze®, Kyoto), and fibrin glue (Bolheal®, Kaketsuken-Teijin Pharma, Tokyo) was sprayed to this seat ( Fig. 3 ). Bleeding was minimal. This white and hard tumor was measured at 21 × 19 × 19 mm.

Nasopharynx after the tumor removal. Blue mesh (PGA sheet) covered the surgical wound behind the tubal orifice (arrow).

The surgical defect gradually healed and was totally covered with normal mucosa with a completely resolved hearing loss three months after the surgery ( Fig. 4 A, B ). No recurrence was observed 2 years after tumor removal. Both tympanic membrane and audiological data recovered completely.

Mucosa became normal, and tubal orifice was fully open without adhesion or scarring (A). No middle ear effusion was observed (B).

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Discussion

Benign tumors arising from the minor salivary glands occur less commonly than malignant tumors. Pleomorphic adenoma is the most common benign tumor of the minor salivary glands, but nasopharyngeal pleomorphic adenoma is rarely described. To our knowledge, there are only five reports about nasopharyngeal pleomorphic adenoma in the English literature . Spino et al. reported 492 cases of tumor that originated from the minor salivary glands, and there were 10 patients with nasopharyngeal tumor among these cases. Only one case was diagnosed with pleomorphic adenoma, and 9 out of 10 nasopharyngeal tumors were malignant . Kuo et al. reported 37 cases of pleomorphic adenoma arising from sites other than the major salivary glands, and 3 out of 37 cases were observed in the nasopharynx . Symptoms of nasopharyngeal pleomorphic adenoma were variously reported, such as nasal obstruction, epistaxis, dysphagia, otalgia, ear obstruction, and hearing loss. Martinez-Capoccioni and Lee et al. reported cases of nasopharyngeal pleomorphic adenoma presenting as OME. One patient recovered and the other had persistent dysfunction of the Eustachian tube after tumor removal . Other two cases also showed hearing loss, but details were not described. The association of OME with adenoid vegetation or nasopharyngeal carcinoma is well known to clinicians. However, other disorders such as choanal polyp or benign tumor of the parapharyngeal space do not always cause OME even if they are large enough to obstruct the Eustachian tube . Additional pathological changes around the Eustachian tube, such as inflammation and invasion to the tensor veli palatini muscle or cartilage of the Eustachian tube, may cause tubal dysfunction leading to OME . In the present case, the tumor adhered to the mucosa and cartilage around the Eustachian tube which caused tubal dysfunction leading to OME.

The treatment of nasopharyngeal pleomorphic adenoma is surgical excision, and several procedures were performed like lateral rhinotomy and transnasal endoscopic approach for other benign tumors arising in the nasopharynx . In the present case, the tumor was successfully removed by a combination of endo-oral and endonasal approaches. However, a large mucosal defect was left, and exposure of posterior surface of the tubal cartilage occurred. Postoperative adhesion, consecutive tubal dysfunction, and OME were concerns.

For this reason, we applied PGA seat to the surgical defect and sprayed fibrin glue to prevent postoperative hemorrhage and scaring. The PGA is absorbable and has high physical affinity to the mucosa. The sprayed mist of fibrin glue deeply infiltrates the inside of the supple PGA seat. Therefore, the PGA seat firmly covered the exposed wound surface even in mobile region like the nasopharynx. Combination of PGA and fibrin glue is used to prevent air, biliary, and cerebrospinal fluid leakage and also to prevent postoperative recurrence of pneumothorax, and minimize bleeding in pulmonary, liver, neural, and spinal surgery . This seat is recently used for covering the exposed surgical wound after removal of oral or oropharyngeal carcinoma . Use of PGA seat not only prevented bleeding but also reduced pain of the wound . In the present case, no postoperative complications, including hemorrhage, developed. PGA seat was gradually absorbed within a month. After that, the mucosa totally covered the surgical defect, and OME spontaneously subsided. We believe the combination of PGA seat and fibrin glue spray is useful for coverage of exposed raw surgical wound in the nasopharynx.