Parapharyngeal space has the shape of a reversed pyramid with the base at the cranial surface delimited by temporal and sphenoid bone and and the top pointing to the large horn of the hyoid bone. Styloid diaphragm divides the parapharyngeal space into two regions with different anatomy and constituents: prestyloid space, anterior, conta-ining the deep lobe of the parotid gland, internal maxillary artery, inferior alveolar nerve, lingual, auriculo-temporal, and retrostyloid space, posterior, neurovascular, that contains the internal carotid artery, internal jugular vein, cranial nerves glossopharyngeal, vagus, accessory, hypoglossal and cervical sympathetic chain. 
Tumors arising in parapharyngeal space are rare, representing less than 1% of all head and neck malignancies. Any of the structures contained in this space can be a starting point for developing a tumor masses at this level. Most of these tumors are benign, approximately 20% are malignant.  The most common tumors of the salivary gland tissue derived from space and are epithelial in nature. Others are likely neurogenic, vascular, lymphatic, etc.