• The parapharyngeal space is shaped like a pyramid, inverted with its base at the skull base, with its apex inferiorly pointing to the greater cornu of the hyoid bone .

•The fascia of the stylopharyngeus, styloglossus, and tensor veli palatini muscles separates prestyloid and poststyloid spaces•styloid process

• Superior margin: base of skull• Inferior : greater cornu of the hyoid bone• Medial : middle layer of deep cervical fascia• Lateral : investing fascia covering the deep lobe

of the parotid• Anterior : investing fascia covering the medial

pterygoid• Posterior : prevertebral fascia

•1. internal maxillary artery•2. inferior alveolar nerve•3. lingual nerve•4. auriculotemporal nerve

• Contents of carotid sheath –>internal carotid artery, internal jugular vein, and cranial nerves 9, 10 and 12.

• Cervical sympathetic chain• Numerous lymph nodes

• Spread of adjacent tumors -nasopharyngeal and oropharyngeal carcinoma, chordoma, and synovial sarcoma

• Minor salivary gland tumors -pleomorphic adenoma• Neurogenic tumors• Lymph nodes• Paragangliomas• Parapharyngeal space abscess• Parotid deep lobe tumors• Branchial cleft cysts

CAROTID ARTERY•Ectasia•Aneurysm•Dissection•Encasement by direct squamous cell carcinoma.

• Asymmetric enlargement• Thrombosis • Thrombophlebitis• Meningioma (from jugular foramen)

• Neurogenic Tumor• Neuroblastoma• Paraganglioma

• Neck mass• Oropharyngeal mass• Unilateral eustachian tube dysfunction• Dysphagia• Dyspnea• Obstructive sleep apnea• CN deficits• Horner syndrome• Pain• Trismus• Symptoms of catecholamine excess

Localizing the lesion

• Displacement of the lateral wall of the pharyngeal space medially,

• Displacement of the parotid gland laterally while maintaining an inta c t fa t p la ne with the deep lobe of parotid gland

• Displacement of the carotid vessels posteriorly

• Anterolateral displacement of the prestyloid parapharyngeal fat.

• Anterior or medial displacement of the internal carotid artery with o blite ra tio n o f fa t p la ne s around the great vessels.

• Extension posterior to the styloid process with its anterolateral displacement.

Pleomorphic adenoma in a 35 yr-old-woman. Contrast enhanced axial CT scan shows a minimally enhancing water attenuation well-defined mass extending into the prestyloid parapharyngeal space with widening of the stylomandibular tunnel.

• Prestyloid/poststyloid compartment?

Axial unenhanced T1-weighted spin-echo MR image shows low-signal-intensity mass . Medial fat line between mass and pharyngeal mucosa is displaced but preserved, whereas lateral fat line between mass and parotid gland is not seen, indicating parotid origin.

Contrast enhanced axial CT scan shows a heterogeneously enhancing Schwannoma with areas of necrosis displacing the internal carotid artery anteromedially.

Neurofibroma in a 22yr-old-man. Contrast enhanced axial CT scan shows the minimally enhancing tumor in the post-styloid space causing anterior displacement of ICA

• Presence of internal flow voids on MR Imaging in a mass that is greater than 2 cm is suggestive of paraganglioma, rather than Schwanoma.

Carotid body tumor in a 26 yr-old-man.

Post contrast axial CT shows intensely enhancing vagale tumor causing anterior displacement of the internal carotid artery

Malignant peripheral nerve sheath tumor Axial T2-weighted spin-echo MR image shows tumor (arrows) is slightly hyperintense to muscle

tumor (arrows) extends into eustachian tube (arrowheads).

Immediately life threatening lesion ??

Skull base extension of the meningioma seen as hyperostosis of the adjacent skull base with a small calcified intracranial infratentorial component

Tumor causing smooth scalloping and widening of jugular foramen ??

schwanoma

Post contrast Axial CT shows a peripherally enhancing right parapharyngeal abscess with air pockets

Tubercular lymphadenitis

Metastatic lymphnodes

• Pleomorphic adenoma is the most common tumor involving the p re s ty lo id compartment.

• Neurogenic tumors commonly involve the p o s ts ty lo id compartment.

Thank you