A Huge Para-pharyngeal Mass: Excision through Trans-cervical Approach

The parapharyngeal space is an inverted pyramid shaped space, its base lies at the skull base and apex points inferiorly to the styloglossus muscle at the level of the angle of the mandible on each side of the neck that extends up to the greater cornu of hyoid bone. The fascia from the styloid process to the tensor veli palatini divides the parapharyngeal space into an anterior (prestyloid) compartment and a posterior (poststyloid) compartment.


Introduction
The parapharyngeal space is an inverted pyramid shaped space, its base lies at the skull base and apex points inferiorly arise from the deep lobe of parotid gland, ectopic salivary gland or in minor salivary glands of the lateral pharyngeal wall. The most common prestyloid PPS lesion is "pleomorphic adenoma" represents 80-90% of salivary neoplasms in the PPS [1][2][3][4]. Many other lesion of this compartment belongs to neurogenic tumors especially Schwannomas, paragangliomas, and lymphoreticular lesions.
In most of the cases the tumor remains asymptomatic and becomes an incidental fi nding. It can present with dysphagia, sore throat, feeling of lump in the throat, neck swelling etc. In this article we present a case of 15 years old girl reported with a huge swelling in the oral cavity.

Case report
A 15 years old beautiful girl presented with a gradually progressive painless swelling in the throat and change in quality of speech for one-year. According to her statement, she was reasonably well 4 years back then she started feeling pricking senation in the throat. While she the girl tried to see Citation: Islam

Discussion
Para-pharyngeal space is a potential space of head and neck that may become involved by various pathological entities such as infections, infl ammatory, and neoplastic. Tumors of this PPS represent less than 1% of all head and neck tumours [5][6][7][8]. Both benign and malignant tumors may arise from any structure contained within the PPS where 70-80% appears belong to benign and 20-30% to malignant. Of the benign tumors pleomorphic adenoma is the commonest [9]. The most common site of a pleomorphic adenoma of the minor salivary gland is on the palate followed by lip, buccal mucosa, and fl oor of mouth [10]. Pleomorphic adenoma of PPS can arise from deep lobe of parotid or ectopic salivary glands [11][12][13], which was correlated in our case.
The presentation is variable, most of these tumors remain A B  asymptomatic for long time but may present with dysphagia, voice change, sore throat, otalgia, lower cranial palsy etc.
Classically the benign lesions are painless, fi rm and mobile. A lateral pharyngeal swelling or a palatal bulging along with medial tonsillar and lateral uvular displacement is diagnostic of a para-pharyngeal mass with or without extension to retromandibular trigone and the submandibular triangle.
In most of the cased the submandibular swelling remains bimanually palpable [6,13,14], that was aptly found in this girl.
The diagnostic workup algorithm begins with hematologic and serologic tests. Fine needle aspiration cytology (FNAC), CT and/or MRI studies should be the part of the preoperative diagnosis to determine the extent of disease, local spread, and even the type of tumor. Preoperative FNAC and was carried out and was diagnostic in our case.
Cross sectional imaging is mandatory to see the extension, character and site of origin of the lesion. MRI is superior then CT as it helps to identify the site of origin. A CT scan is cost effective and with contrast ascertains the vascularity of tumors and their relationship to adjacent neurovascular structures. The presence or absence of fat planes between the tumor and adjacent structures and the direction in which the tumor displaces the fat plane helps to determine whether the tumor is located in the pre-styloid or post-styloid compartment and whether the site of origin is the parotid gland [5,8,15]. In addition, a CT scan provides a precise defi nition of the skeletal framework, demonstrating bone remodeling, expansion, or destruction.
The mainstay of treatment of tumors of the parapharyngeal space is surgical extirpation.though choice of surgical approach is challenging due to its location with cranial nerves, great vessels sympathetic chain [15]. Complete excision of the tumor is recommended to corroborate the diagnosis suggested by the clinical examination and imaging. Several approaches has been recommended like-Transoral, Transcervico-Submaxillary, Transcervical, Transmandibular, Transparotid, Infratemporal Fossa approach [16][17][18], etc. However different approaches have individual co-morbidity. In an encapsulated tumor of PPS, trans-cervical approach remains benefi cial as mandibular splitting can be avoided though there is chance of marginal mandibular nerve injury, but can easily be avoided. In our case we used the submandibular trans-cervical approach and the mandible was retracted superiorly for better exposure and mass can be removed by blunt dissection.

Conclusion
It is challenging for a surgeon to choice the best approach to a para-pharyngeal space tumor without morbidity Cross sectional imaging is best to diagnose and assess extension of the tumor; and it also aids to choose the surgical approach.