Retrostyloid parapharyngeal space tumors: a clinician and imaging perspective.

Although tumors of the parapharyngeal space are rare, they represent a formidable diagnostic and treatment challenge. The differentiation of a retrostyloid lesion from a prestyloid lesion is critical for guiding the differential diagnosis. The majority of lesions involving the retrostyloid parapharyngeal space are either peripheral nerve sheath tumors, head & neck paragangliomas or metastatic lymph node metastases. This article provides insights into the many currently available radiological and radionuclide imaging procedures and guides clinicians toward their appropriate use. In the near future, many patients might also benefit from new diagnostic approaches such as high resolution integrated PET/MRI and new tracers that enable "in vivo" assessment of these tumors at molecular level.