Return to: Neck Surgery Protocols

See also: Case Example Deep Lobe Parotid Tumor Parapharyngeal Space Pleomorphic Adenoma

Pleomorphic Adenoma

Vagal Schwannoma - Rads

Anatomy (Price 2016)(Bozza 2009):

• Inverted pyramid space, base centered on small portion of temporal bone, and the apex at the greater cornu of the hyoid bone.
• Compartmentalized by the styloid process and a band of fascia extending from the styloid process to the tensor veli palatini into: (I) Prestyloid, and (II) Poststyloid (retrostyloid, carotid space).
• Boundaries:
  • Anterior: pterygomandibular raphe, fascia of the medial pterygoid muscle. The masseteric space immediately anterior to the parapharyngeal space.
  • Posterior: prevertebral fascia, paravertebral musculature.
  • Medial: (I) Superiorly: fascia from tensor veli palatini to medial pterygoid muscle. (II) Inferiorly: fascia over superior constrictor muscle. (II) Posteriorly: pharyngobasilar fascia.
  • Lateral: fascia overlying medial pterygoid muscle and mandibular ramus.
  • Inferior: posterior belly of the digastric muscle.

Contents:

Presentation (Price 2016)(Bozza 2009):

• Most often asymptomatic incidental finding.
• Fullness of tonsillar region, can be mistaken for peritonsillar abscess, the later present with sore throat, fever, tenderness, exudates, leukocytosis.
• Neck mass, in third of the patient associated with aural pressure or pain.
• Cranial nerve deficit, most likely with malignancy.
• Secreting paragangliomas tumors presents with headache, labile hypertension, palpitations, and sweating.

Evaluation (Price 2016)(Bozza 2009):

• Physical examination usually unremarkable.
• Imaging is critical, either CT or MRI, provides information on the underlying pathology, prestyloid vs. poststyloid, and relationship to the surrounding structures.  
• Biopsy can be considered, however is often unnecessary. Fine needle aspiration with direct palpation, ultrasound, or CT for guidance. Transoral biopsy is dangerous can lead to the tumor adherence to the pharyngeal mucosa and possible severe hemorrhage.  
• Angiography is recommended for all enhancing lesions or vascularised masses, particularly if imaging shows a widening of the carotid bifurcation.
• If secreting paragangliomas is suspected, lab workups include serum catecholamines, and 24hr urine vanillylmandelic acid, metanephrines, dopamine, epinephrine, and norepinephrine. 

Types of tumors (Price 2016)(Bozza 2009)(Olsen 1994):

Parapharyngeal space tumors are rare and account for 0.5% of head and neck tumors, 80% benign and 20% malignant

• Salivary gland neoplasms (benign to malignant ratio 3:1): majority of parapharyngeal space tumor, mostly in the prestyloid space.
• Neurogenic neoplasms: second most common, mostly in the poststyloid space. The most common neurogenic neoplasms are: vagal schwannomas, sympathetic trunk schwannomas, and vagal paragangliomas.
• Vascular and lymphatic lesions: aneurysms, hemangiomas, hemangiopericytomas, lymphatics malformation.
• Others: lipomas, sarcomas, lymphoma.
• Metastatic lesions: squamous cell carcinoma of the nasopharynx, oral cavity, & oropharynx. Thyroid cancer.

Surgical approaches (Price 2016)(Bozza 2009):

• Transoral, can be with robotic assistance. Preferred for prestyloid small tumor. Does not allow for full identification of regional nerves and vessels. See: Transoral Robotic Surgery
• Transcervical
• Transparotid - transcervical
• Transcervical - transmandibular

References

Price LS, Olsen KD. Tumors of parapharyngeal space. In: Gullane PJ, Goldstein DP, eds. Sataloff's comprehensive textbook of otolaryngology: Head and neck surgery. Vol 5. First ed. India: Jaypee Brothers Medical Publishers; 2016:471. Accessed November 11, 2016.

Bozza F, Vigili M, Ruscito P, A. Marzetti, Marzetti F. Surgical management of parapharyngeal space tumours: results of 10-year follow-up. Acta Otorhinolaryngologica Italica. 2009;29(1):10-15.

Olsen KD. Tumors and surgery of the parapharyngeal space. Laryngoscope. 1994;104(5 Pt 2 Suppl 63):1-28.