Diagnosis and treatment of parapharyngeal space tumors

Abstract

The parapharyngeal space extends from the nasopharynx to the oropharynx. It is bordered medially by the pharyngeal wall and the constrictor pharyngis muscles, and laterally by the mandible. One distinguishes between apre- and a poststyloid space. Tumors of the parapharyngeal space are rare and represent less than 1 % of all head and neck neoplasms. Benign (70-80 %) as well as malignant (20-30 %) tumors arise from different structures of the parapharyngeal space, mainly from salivary glands and nerve structures. Concerning salivary gland tumors, most are pleomorphic adenomas typically appearing in the prestyloid space, whereas the schwannomas that may also arise are located in the poststyloid space. The main symptom is dysphagia, with the tumor generally presenting as avisible bulking of the pharyngeal wall, in rare cases also as an externally visible cervical mass. Treatment is generally surgical resection, particularly in benign tumors, preferably via transcervical access. If R0resection of malignancies is possible, this should be performed. In malignant lymphomas and nonresectable tumors, primary chemo-, radio-, or combination therapy should be considered after histologic confirmation. For neurogenic tumors, particularly vagal nerve schwannoma and especially in older patients, a wait-and-scan strategy is most favorable, since postoperative vagal palsy is unavoidable with surgical resection. Treatment planning for parapharyngeal space tumors requires good knowledge of topographic anatomy and careful evaluation of imaging findings.