Parapharyngeal space tumors: surgical approaches in a series of 13 cases

Abstract

Tumors originating in the parapharyngeal space are rare; they comprise approximately 0.5% of head and neck tumors. Most (70–80%) are benign and the most frequent origins are salivary and neurogenic. The aim of this study is to present the surgical procedures used for the treatment of 13 patients with parapharyngeal space tumors; 11 of them were suffering from benign tumors (the most frequent being pleomorphic adenoma; 8 cases) and 2 from malignant lesions. The following surgical approaches were used: intraoral (2 cases), transcervical (4 cases) and transmandibular (7 cases) with different types of mandible osteotomies. The type of surgical approach was dictated by the type of the lesion (malignant or benign), the exact location, the size, the vascularity and the relation of the tumor to the neck neurovascular bundle. In all cases the selected surgical approach allowed the complete resection of the tumor, obtaining clear margins in cases of malignancy, without adding to the patient’s preoperative morbidity. It was concluded that the surgical approach to the parapharyngeal space tumors must be adjusted to the tumor characteristics and be as wide is necessary to achieve its complete removal with safety.

Parapharyngeal space (PPS) tumors are rare and comprise approximately 0.5% of head and neck tumors . A wide variety of neoplasms occur in this anatomical region but most (70–80%) are benign and the most frequent origins are salivary and neurogenic . The most frequent neoplasm of salivary gland origin is pleomorphic adenoma while paraganglioma is the most common neurogenic PPS tumor .

The PPS anatomy makes diagnosis and therapy of PPS tumors difficult. The complex relations of vital tissues make surgery to remove the tumor difficult without adding to the patient’s preoperative morbidity. Various surgical techniques have been developed to provide effective and safe access to the PPS.

This study presents the authors’ experience with 13 primary PPS tumors treated surgically during the last 5 years. The diagnostic and therapeutic procedures are presented, focusing on the surgical approaches used.

Materials and Methods

During the past 5 years, 13 patients have been treated surgically for primary PPS tumors. This study was limited to patients with primary PPS tumors, while patients with tumors originating elsewhere and extending into the PPS were not included. 6 patients were excluded who were surgically treated during the same period for primarily oropharyngeal and parotid carcinomas extending into the PPS. None of the patients included in this study had previously received therapy (surgery, radiotherapy or other) for their PPS tumor.

The following data were collected for each patient: gender, age, symptoms and clinical examination findings, size of the tumor, surgical approach, histological diagnosis, additional therapy, complications, follow-up time and outcome. All patients underwent full laboratory examinations. Computed tomography (CT scan) and/or magnetic resonance imaging (MRI) were used to define the exact location and the size of the tumor. In one case, in which high vascularity was presumed from the MRI, a digital angiography was performed. Preoperative fine needle aspiration (FNA) biopsies (CT-guided or not) or open intraoral biopsies were performed in 12 patients, in whom the nature of the tumor (not very vascular) allowed these procedures, in order to determine if the lesion was malignant or benign.

All 13 patients were treated with surgical removal of the PPS tumor. For every patient an individualized surgical approach was selected, depending on the suspicion of malignancy (on clinical, imaging, and, if available, FNA or open biopsy ground), the size of the tumor, its exact location and its relation to the neck great vessels. Intraoral, transcervical and transmandibular approaches were used.

The intraoral approach was used when the patient’s history, clinical and imaging findings, or FNA results indicated that the PPS lesions were benign. In addition, the tumors were small (up to 2 cm), the patient’s main symptom was a pharyngeal mass and the tumor projected into the oropharynx causing soft palate displacement.

The transcervical approach was used for presumably benign tumors of large size (>2 but <4 cm), when the patient’s main symptom was a neck mass. The tumor was located in the poststyloid PPS compartment in all cases. During the transcervical approach the submandibular salivary gland was retracted and preserved, and the neurovascular bundle of the neck was identified, dissected and protected.

For the transmandibular approach, the authors defined surgical procedures that included one or more osteotomies of the mandible, after a submandibular incision. In cases where very wide access was needed, an inferior lip-split was added to the submandibular incision.

The types of mandible osteotomies used in the patients in the study were: paramedian (PMO) and vertical subsigmoid (VSSO) with or without a coronoidectomy (COR). The type of the osteotomy was selected depending on the width of the access required. The VSSO alone was used only in one case, where the tumor was very close to the ramus of the mandible. As the PMO provides wider access than the VSSO, in cases of tumors of larger size and deeper location this osteotomy was preferred. In cases where even wider access was needed, a combination of osteotomies was adopted. In all cases where a transmandibular approach was used, the neurovascular bundle of the neck was identified, dissected and protected before mandible osteotomy. In every case where a PMO was used, a paralingual incision was made up to the posterior floor of the mouth, to help the surgeons perform the mandibular swing and expose the PPS widely.

The transmandibular approach was adopted in cases in which the patient’s preoperational data (history, clinical and imaging findings or FNA results) indicated a benign PPS tumor of large size (>4 times 4 cm). In one case, preoperative imaging findings showed a very vascular tumor. 4 days before surgery a preoperative embolisation was performed in order to reduce intra-operative blood loss and the surgical procedure was a transmandibular approach with a lip-split for a wider access.

The transmandibular approach was used in cases in which the patient’s history, clinical and imaging findings, FNA or open biopsy results favoured a malignant diagnosis. It was used in one case with a preoperative FNA diagnosis of adenocarcinoma (the postoperative final histopathological diagnosis was a synovial sarcoma) and in another case with a preoperative diagnosis of adenocarcinoma on the basis of an intraoral open biopsy. In these two cases a transmandibular approach with a lip-split was performed for wider access in order to obtain clear margins.

In cases in which a very wide approach was adopted (transmandibular approach with an additional lip-split) a prophylactic tracheotomy was performed and was abolished 4 days postoperatively.

Follow-up for patients with benign tumors included clinical examination after 1, 3, 6, 12 and 24 months and a head and neck MRI 6 months postoperatively, in order to detect possible recurrence of the disease. Every patient with a malignant tumor was examined once a month for the first year, once every 3 months for the second year and once every 6 months for 5 years after treatment. Additionally, these patients underwent a head and neck CT and/or MRI every 6 months for the same period. These patients will remain under observation until the authors are able to reach to conclusions about their disease course and the 5-year-survival.

Results

This series consisted of 13 patients surgically treated for primary PPS tumors and included 7 women (54%) and 6 men (46%) with a mean age of 46.3 years (range 22–72 years). The patients’ most common main symptoms were awareness of an intraoral/pharyngeal or a neck mass (92%) and dysphagia (31%), two patients suffered from dysarthria (15%) and one from hoarseness (8%). Pain was present only in the two cases of malignant neoplasms (15%). The most common findings on clinical examinations were the presence of a palpable neck mass posterior to the mandibular angle (77%) or an intraoral/pharyngeal mass (62%) causing a swelling of the lateral pharyngeal wall and the displacement of the soft palate and/or the tonsil. Five patients (39%) had an intraoral/pharyngeal and a palpable neck mass. Three patients (23%) had developed a XII deficit, two patients presented an IX deficit, while only one patient had true vocal cord palsy and was referred with hoarseness ( Table 1 ).

Table 1
Patient data.
Gender Age Main symptoms Clinical examination findings Size (in cm) Surgical approach Histological diagnosis Additional therapy Complications Follow-up time (months) Outcome
Male 38 Neck mass Dysphagia Neck mass 4.5X3X2 Transmandibular (PMO) Pleomorphic adenoma Hematoma 50 NED
Phar. mass
Male 48 Pain Neck mass 4X3.5X3 Transmandibular (PMO)+LS Synovial sarcoma Postoperative 14 Brain metasta-sis
Neck mass XII deficit Radiotherapy
Chemotherapy
Female 72 Phar. mass Phar. mass 2X2X2 Intraoral Pleomorphic adenoma 6 NED
Female 37 Neck mass Neck mass 3X3X2.5 Trancervical Branchial cleft cyst 63 NED
Male 42 Neck mass Neck mass 4.5X3X2 Transmandibular (VSSO) Pleomorphic adenoma 58 NED
Phar. mass
Female 72 Dysphagia Dysarthria Hoarseness Phar. mass 6X4X3.5 Transmandibular (PMO)+LS Vagal para-ganglioma Preoperative Embolisation Temporary MMB neuropathy 16 NED
True vocal fold palsy
IX deficit
XII deficit
Female 39 Phar. mass Phar. mass 2X2X1.5 Intraoral Pleomorphic adenoma 38 NED
Male 22 Neck mass Neck mass Phar. mass 5X3.5X3 Transmandibular (VSSO+PMO+COR) Pleomorphic adenoma 5 NED
Female 47 Pain Neck mass 4.5X3X3 Transmandibular (PMO+COR)+LS Adenocarci-noma Postoperative Temporary MMB neuropathy 54 NED
Neck mass Phar. mass Phar. mass Radiotherapy
Dysphagia Dysarthria Parotid mass IX deficit
XII deficit
Male 44 Neck mass Dysphagia Neck mass 5X3.5X3 Transmandibular Neurofibroma Temporary 48 NED
Phar. mass (PMO+COR) XII neuropathy
Male 49 Neck mass Neck mass 3X3X2 Trancervical Pleomorphic adenoma 26 NED
Female 41 Neck mass Neck mass 3.5X3X2 Trancervical Pleomorphic adenoma 19 NED
Female 52 Neck mass Neck mass 3X2.5X2 Trancervical Pleomorphic adenoma 29 NED
LS, lip-split; PMO, paramedian mandibular osteotomy; VSSO, vertical subsigmoid osteotomy; COR, coronoidectomy; MMB, marginal mandibular branch of the facial nerve; NED, no evidence of the disease; Phar., pharyngeal.
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Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Parapharyngeal space tumors: surgical approaches in a series of 13 cases
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