Página del Residente

¿What surgical approach should be used?

¿Cuál seria su abordaje quirúrgico?

A 74 year-old male patient was referred to our service by his dentist due to a tumor-like bulge in his soft palate. The lesion was painless and it was not producing any other accompanying symptomatology.

With regard to his personal history, only an antibiotic allergy to beta-lactam and streptomycin was of significance.

On physical exploration a tumor-like bulge was noted that was deforming the right soft palate. It measured 4 x 4 centimeters approximately in diameter. It was hard, movable and not painful on palpation. No pathological findings were noted on examination of his neck. In order to complete the diagnostic and extension study, we requested a FNA of the lesion and a CT scan of the face and neck with intravenous contrast. The microscopical diagnosis of the FNA (Fig. 1) was of a salivary gland with images suggesting Pleomorphic adenoma. And in the CT scan (Fig. 2) it was reported as a lesion extending from the plane of the hard palate to the floor of the mouth along the craniocaudal axis, and measuring approximately 4 centimeters in the anteroposterior and transverse diameter. The lesion was causing the right parapharyngeal space to be displaced towards the left, and it was affecting the airway and the right retropharyngeal and prevertebral spaces. A sideways displacement of the pterygoid muscles could be observed. Locating the lesion in the parotid space or in the mucosal-submucosal oropharyngeal space was difficult. Nonspecific lymph nodes appeared along all the cervical chains.

With the results of the FNA and the CT scan the presumed diagnosis of Pleomorphic Adenoma of the right parapharyngeal space was made, and surgical excision was programmed.

Pleomorphic adenoma of the parapharyngeal space. Excision using the transoral approach.

Adenoma pleomorfo en espacio parafaríngeo. Extirpación a través de abordaje transoral

L. García-Arana¹, M. Chamorro Pons²

1 Médico residente.
2 Médico adjunto.
Servicio de Cirugía Oral y Maxilofacial Hospital Universitario La Paz, Madrid, España.

Correspondencia:
Dra. García Arana
C/ Antonio López Aguado 4
28029, Madrid, España
E-mail: lgarciaa.hulp@salud.madrid.org

Discussion

The excision of tumors in the parapharyngeal space can be difficult due as much to surgical access being complicated as to the important neurovascular structures crossing the zone. In order to attain a proper surgical site, cervical and facial approaches are frequently required, which often include a mandibulotomy with or without a coronoidectomy. ¹ This is aggressive for the patient, who is exposed to greater surgical morbidity (such as the risk of damage to the dental and lingual nerves).

The pleomorphic adenoma is the most frequent benign tumor of the salivary glands, comprising of more than two thirds of all parotid tumors (80% of all the tumors of the salivary glands in adults) and more than half of the tumors of the submaxillary and minor glands.² Bilateral tumors are not very frequent. They are characterized histologically, as their name indicates, by their structural complexity and pleomorphism, as they are made up of a combination of epithelial and myoepithelial cells in a mesenchymal stroma. Recurrence takes place fundamentally in cases of incomplete excision of primary tumors, or accidental rupture during surgery and, given that the tendency towards malignancy is greater, they should be completely excised. Malignancy of primary tumors occurs in 3 to 5% of cases (generally adenocarcinomas or undifferentiated carcinomas) and the tendency is greater in cases of rapid clinical evolution and in elderly patients. It is infrequently found in the parapharyngeal space and its diagnosis comes late, as the tumor grows silently from a minor salivary gland as in this case, or from the deep lobe of the parotid gland in a medial direction (latterly its growth is limited by the ascending ramus of the mandible). It is generally during a medical examination of the oral cavity that the existence of a mass in the soft palate is discovered, and the suspected diagnosis is then made.

On reviewing this data one realizes that the pleomorphic adenoma of the salivary glands is a very frequent pathology in the service of the Maxillofacial surgeon. Given its benign nature, it is important to analyze the less aggressive approaches in our therapeutic arsenal in order to remove it. In this case we decided on a transoral approach, already described by Ehrlich² in 1950 in order to reach a tumor of the deep lobe of the parotid located in the parapharyngeal space. With general anesthesia an incision was made in the right jugal mucosa through the oral cavity (Fig. 3). With the aid of some surgical magnifying glasses an encapsulated friable tumor was dissected and removed from the right parapharyngeal space. A drain was placed and suturing was done with 2-0 Vicryl. No complications arose during the postoperative period and as he progressed favorably was able to follow a processed food diet and the drain was removed the day after the surgery. The patient was released three days after the intervention with instructions to follow a soft diet and to maintain strict oral hygiene. He was put on a course of antibiotics containing clindamycin with metamizol for pain relief taken orally. The anatomopathological report confirmed the result of encapsulated pleomorphic adenoma (Fig. 4).

Given that the site obtained through the oral cavity is not very wide, we should not forget that we can rely on the aid of two great allies: the surgical microscope and magnifying glasses. Both instruments will facilitate the work of the surgeon.

On attempting a cutaneous approach of the pharyngeal space we find that access is impeded by the styloid process, the stylomandibular ligament and the ascending ramus of the mandible. This has led to many authors proposing various types of mandibular osteotomies with the aim of facilitating this access.^1,4,5 Many of these techniques put into danger the integrity of the inferior alveolar and lingual nerves, requiring the execution of a superficial parotidectomy (with the accompanying short and long term lesions), representing a very considerable increase in surgical morbidity. Added to this, cost is increased significantly (titanium osteosynthesis) together with operating time.

When confronted with benign tumors, such as the type presented in this case, carrying out surgical techniques as conservatively as possible is advisable. On numerous occasions we carry out very complex approaches putting the patient at unnecessary risk. It is important to stress the advantages of using approaches that are as simple as possible, according to the characteristics of the tumor, which will always be to the patient's advantage and a great satisfaction for the surgeon. With regard to the anatomical cavities such as the nasal pit or oral cavity, it would seem logical that as a first option dissection should take place through these, thus sparing the patient much of the morbidity associated with the surgery. These anatomical possibilities should be emphasized because as maxillofacial surgeons we often forget them, initially considering transfacial or transcervical approaches, which give excellent visibility, but with a morbidity cost that is unacceptable in many cases.

We should, however, acknowledge that the transoral approach is not of choice in all tumors of the parapharyngeal space.6 In every case two fundamental factors should be taken into consideration: obtaining adequate visibility in order to eradicate the tumor, and that the functional and aesthetic consequences for the patient should be minimal. Thus, in the case of malignant tumors that require radical excision, we should use in general more aggressive approaches that provide us with larger surgical sites.

All the bioethical committees are currently admitting the importance of the principle of negative cost compared with benefit, that is to say, we must never cause in our patients more harm than good. In the case of benign tumors this must be kept in mind during surgical planning, and complex approaches are therefore not acceptable when simpler options that are equally efficient exist.

In conclusion, the use of an approach through the oral cavity in order to resection benign tumors of the parapharyngeal space is, in our opinion, a valid option, which is hardly aggressive, and that should always be kept in mind by the Maxillofacial surgeon.

References

1. Lazaridis N, Antoniades K. Double mandibular osteotomy with coronoidectomy for tumours in the parapharingeal space. Br J Oral Maxillofac Surg 2003;41:142- 6.        [ Links ]

2. Harney MS, Murphy C. A histological comparison of deep and superficial lobe pleomorphic adenomas of the parotid gland. Head Neck 2003;25:649-53.        [ Links ]

3. Ehrlich H. Mixed tumours of the pterigomaxillary space: operative removal, oral approach. J Oral Surg 1950;3:1366-70.        [ Links ]

4. Ariel IM, Jerome AP, Fack GT. Treatment of tumours of the parotid salivary gland. Surgery 1954;35:124-8.        [ Links ]

5. Biedlingmaier JF, Ord R. Modified double mandibular osteotomy for tumours of the parapharingeal space. J Oral Maxillofac Surg 1994;52:348-56.        [ Links ]

6. Anderson PJ, McLean NR. Management of a large pleomorphic adenoma of the parotid gland. Eur J Surg Oncol 1999;25:330-1.        [ Links ]