Role of 18F-FDG PET Scan in Parapharyngeal Space Tumors: Report of a Rare Case and Review of the Literature

Abstract

BackgroundParapharyngeal space (PPS) tumors are rare, accounting for 0.5% of all neoplasms of head and neck. PPS tumors may be primary, metastatic or a direct extension of tumors from the adjacent spaces. The frequency of benign and malignant tumors is about 80% and 20%, respectively. Most of them originate from the salivary gland (40-50%), followed by a neurogenic etiology and the remainder are a broad spectrum of miscellaneous tumors [1][2][3][4][5][6][7].The PPS is a lateral pharyngeal region. It is divided by muscular aponeurotic partition into an anterior (prestyloid) muscular compartment and a posterior (poststyloid) neurovascular compartment [1,[3][4][5][6][7]. Imaging is crucial for the assessment of PPS tumors. Surgery is performed based on information provided by these diagnostic modalities.This article will present a case of left parapharyngeal squamos cell carcinoma with unusual spinal metastases, and the potential role of FDG PET/CT will be illustrated. Case PresentationA 36-year-old male patient who showed up in April 2016 with 3 months' history of left side facial paralysis, left trismus, difficulty in swallowing and otological symptoms: otorrhea and otorrhagia. For the last month, he had developed a pharyngeal cavity mass. CT scan head and neck showed well defined heterogeneously enhancing left parapharyngeal solid mass (32×50×62 mm) with multiple area of necrosis, bulging into nasopharynx with extension to pharyngeal mucosal surface.The mass overwhelms the tympanic cavity and spreads to the ipsilateral external auditory meatus and pterygoid muscle. It causes the AbstractBackground: Tumors of the parapharyngeal space (PPS) are rare and account for only 0.5% of head and neck neoplasms. Approximately 80% of these tumors are benign lesions, yet they represent a formidable diagnostic and treatment challenge. They are difficult to diagnose because they have few symptoms, therefore, CT and MRI are essential to delineate the tumor extent, intracranial involvement and relationship to the adjacent vital structures.

Surgical Management of Parapharyngeal Tumors: Our Experience

“…The role of PET/CT is limited as a diagnostic modality; however, it can be used to rule out distant metastasis in malignant tumors. 9 In our study, primary modality, MRI was done in 42 patients, while CECT was done in 16 patients. PET/CT was done in only two patients presenting with metastases.…”