1. Parapharyngeal Space Tumors
Ihab Samy, M.D.
Lecturer of Surgical Oncology
National Cancer Institute,Cairo-Eypt
2013

2. • Account for 0.5 - 1% of all head and neck
neoplasms
• Benign: 80% and Malignant: 20%
• Surgical excision is the primary treatment.

3. Anatomy
• Inverted pyramid with
floor at skull base, tip
at hyoid
• Potential space

4. Superior Boundary
• Small portion of
temporal and
sphenoid bones

6. • Inferior: junction of the posterior belly of the
digastric muscle and greater cornu of the
hyoid bone.
• Medially: buccopharyngeal fascia over the
superior constrictor muscle.
• Laterally: fascia overlying the medial
pterygoid muscle, the ramus of the mandible,
and the fascia overlying the retromandibular
parotid.

7. • Anterior: the pterygomandibular raphe.
• Posterior: the dorsal layer of fascia of the
carotid sheath.
Internal carotid artery, jugular vein, CN IX-XII,
sympathetic chain all course through this
space.

9. Prestyoid vs Retrostyloid
• Key anatomical division of PPS
• Tensor-vascular styloid fascia divides into
prestyloid and retrostyloid spaces
• Antero-lateral prestyloid/posteror-medial
retrostyloid
• Used to make differential diagnosis based on
imaging.

10. Prestyloid space
• Located in the
anteromrdial aspect of
the parapharyngeal
space
• Contains the
retromandibular
portion of the deep
lobe of the parotid
gland, adipose tissue,
small nerves, and
ectopic salivary tissue,
and lymph nodes.
Poststyloid space
• Located in the
posterolateral aspect of
the parapharyngeal
space
• Contains the carotid
artery, jugular vein,
cranial nerves
IX,X,XI,XII, the
sympathetic chain,
paraganglia,and lymph
nodes.

12. Prestyloid compartment
• Fat (Adipose tissue).
• Retromandibular parotid.
• Lymph nodes.

13. Retrostyloid compartment
• Internal carotid artery.
• Jugular vein.
• Sympathetic chain.
• Cranial nerves IX-XII.
• Lymph nodes.

14. Prestyloid space
• 40-50% are salivary gland neoplasms.
• 80-90% are benign- pleomorphic adenoma.
• 20% are malignant- mucoepidermoid ca.,acinic
cell carcinoma or carcinoma ex pleomorphic
adenoma.
• Major vessels are displaced posteriorly and
parapharyngeal fat pad displaced medially

15. Poststyloid Space
• 20-30% are neurogenic in origin.
• Schwannoma accounts for the most common
benign tumor, followed by paragangliomas
and neurofibromas.
• Major vessels are displaced anteriorly

16. Stylomandibular Tunnel
• Posterior ramus of the mandible
• Stylomandibular ligament
• Skull base
• Path for deep parotid tumors

20. Primary Tumors
Three categories:
•Salivary gland tumors.
•Neurogenic tumors.
•Miscellaneous tumors.

21. Salivary Gland Tumors
• Most common PPS neoplasms: 40-50%.
• Prestyloid masses.
• Pleomorphic adenoma 80-90%.
• Mucoepidermoid ca. most common
malignancy.
• Less than 5% parotid tumors involve the PPS.

22. Salivary Gland Tumors
• Located in prestyloid space.
• From deep lobe of parotid or minor salivary
glands.
• On CT or MRI a fat plane between the parotid
and a prestyloid mass indicates minor salivary
gland origin.
• Displace the internal carotid posteriorly.

23. Neurogenic Tumors: 17-25%
• Schwannoma or neurilemminoma.
• Paraganglioma.
• Neurofibroma.

24. Schwannoma
• Most common neurogenic neoplasm.
• Vagus, sympathetic chain most common site
of origin.
• Benign and slow growing.
• Generally doesn’t affect nerve of origin.
• Less than 1% malignant.
• Displace internal carotid anteriorly.

25. Paraganglioma
• Second most common.
• Arise from vagus, from carotid body, or from jugular
bulb.
• Bilateral 10%, familial 30%.
• Part of MEN IIA or IIB (medullary thyroid carcinoma,
pheochromocytoma, parathyroid hyperplasia- with
or without mucosal neuromas).

26. • Secrete catecholamines 1-3%.
• Malignant 3-10%.
• Glomus vagale displace carotid anteriorly
• Carotid body tumors splay internal and
external carotid – “lyre” sign

27. Neurofibromas
• 3rd
most common neurogenic tumor.
• From Schwann cells and fibroblasts
• Non-capsulated (involve nerve).
• Multiple.
• Part of Neurofibromatosis type I.

28. NF1
•Affects one in 3,500 births.
•Affects the peripheral nervous system.
•Is caused by a mutation in the NF1 gene on
chromosome 17.
•Is characterized by:
1.6 or more cafe-au-lait spots (light brown
spots similar to birthmarks) on the skin.
2.Pea shaped bumps on or under the skin
(neurofibromas).
3.Large areas on the skin that look enlarged
(plexiform neurofibromas).
4.Freckling in the groin area and under the
arms.
5.Spots on the iris of the eye (Lisch nodules).
6.Skeletal abnormalities such as scoliosis,
bowing of the legs, or thinning of the shin
bones.
7.50% of people with NF1 have learning
disabilities.
NF2
• Affects one in 40,000 births
• Affects the central nervous system
• Is caused by a mutation in the NF2 gene
on chromosome 22
• Is characterized by:
1. multiple brain and spinal tumors
2. tumors on both auditory nerves
3. Manifestations commonly include:
• - deafness
• - balance problems
• - facial nerve paralysis
• - spinal cord compression
• - loss of mobility
• - optic nerve tumors
• - eye function problems
• - cataracts
• - vision loss

29. Miscellaneous Tumors
• Wide variety of tumors
• 20% of total PPS tumors
• Lymphoma, hemangioma, teratoma,
lipoma, branchial cleft cyst, arteriovenous
malformation, internal carotid artery
aneurysm

30. Clinical evaluation
• Deep neck space so
must reach 2-3 cm
before palpable.
• Neck mass 53%.
• Oropharygeal bulge
51%.

31. • Dysphagia, dyspnea,
• Unilateral effusion
• pulsatile tinnitus,
bruit, thrill, otalgia
• airway obstruction,
• hoarseness
• Horner’s syndrome,
• dysarthria,
• hypertension,
flushing

32. • Complete head and neck exam
• Bimanual palpation
• Classically, paragangliomas mobile anterior-
posterior but not up and down
• FNA after imaging.

33. • If paraganglioma is suspected need to check
24 hour urine for catecholamines: VMA,
metanephrines, etc
• Metaiodinated benzylguanidine (MIBG)

34. Imaging
• CT
• MRI/MRA
• angiography

35. CT
• Locates tumor to prestyloid vs retrostyloid.
• Fat plane between mass and parotid
• Displacement of carotid Artery.
• Enhancement of the lesion.
• Bone erosion due to malignancy.
• Limited soft tissue detail  MRI.

37. MRI
• Most useful study.
• Relationship of mass and carotid more easily
seen than with CT.
• Characteristic appearances of tumor types on
MRI allows preoperative Dx in 90-95% of
patients.

38. Pleomorphic adenoma
• Low signal intensity on T1
• High signal intensity on T2
• Displace carotid posteriorly
NB:NB: T1 images cause fat to appear bright, fat like
the myelin in white matter.
T2 weighted images cause water to appear
bright like CSF and fat is dark.

40. Schwannoma
• High signal intensity on T2
• Displace carotid anteriorly

42. Paraganglioma
•“Salt and pepper” appearance
•Displace carotid anteriorly

44. Angiography
• Used to all enhancing lesions.
• Gold standard for relationship to great
vessels.
• Differentiate neurogenic and vascular.
• Remember “lyre” sign.
• Balloon occlusion test if possible sacrifice of
ICA.

45. “Lyre” sign

46. Treatment
• Mainly surgical excision.
• Radiation therapy and chemotherapy mainly
for:
1-Poor surgical candidates.
2-Unresectability.
3-Failure of balloon occlusion test.

47. • Tumor embolization can be performed on
paragangliomas 24 hours prior to procedure.
• May cause fibrosis making dissection difficult.

48. Surgical Approaches
• Depends on the location, size, vascular status,
and suspicion for malignancy.
• Goal is to achieve optimal exposure and
vascular control without significant morbidity.

49. Surgical approaches
• Trans-oral.
• Trans-cervical +/- Mandibulotomy.
• Trans-parotid.
• Cervical-transpharyngeal “swing”.
• Infratemporal fossa.
• Transcervical-transmastoid.

50. Transoral
• Has been used for small, benign tumors.
• Very limited exposure and view.
• Increased risk of tumor spillage.
• Poor vascular control and risk of injury to
neurovascular structures.
• Not recommended.

51. Trans-cervical
• With or without
mandibulotomy
• Transverse incision at level of
hyoid, two fingers breadth
below the mandible.
• Submandibular gland
displaced or removed.
• Increase exposure by
releasing digastric, stylohyoid,
styloglossus from hyoid bone
• Cut stylomandibular ligament
+mandibulotomy

52. Transparotid
• For deep lobe parotid tumors.
• Superficial parotidectomy.
• Facial nerve retracted.
• Dissect around mandible.
• May use mandibulotomy.

53. Cervical-parotid
• Extend cervical incision up infront of ear.
• Allows identification facial nerve.
• Divide posterior belly digastric
• Divide stylomandibular ligament, styloglossus,
stylohyoid close to styloid process.
• Can use mandibulotomy.

54. Cervical-transpharyngeal
• “mandibular swing”
• Large (greater than
8cm)
• Highly vascular tumors.
• Mandibulotomy
anteriorly, incise along
floor of mouth to
anterior tonsillar pillar
• Need a tracheostomy

55. Infratemporal fossa
• Preauricular lateral infratemporal fossa
approach.
• Skull base +/- intra-cranial extension or
infratemporal fossa involvement.
• Can combine with frontotemporal
craniotomy.

56. Transcervical-transmastoid
• Cervical incision
carried postauricularly
• cortical
mastoidectomy.
• Remove mastoid tip
exposing jugular fossa
• Utilized to resect
glomus vagale and
jugulare tumors

58. Nonsurgical Management
• Poor surgical canidates, failed balloon
occlusion, elderly, unresectable lesions, would
require sacrifice of multiple cranial nerves
• Observation
• Radiation

59. Observation
• Paraganliomas grow 1.0-1.5 mm per year
• Benign
• Mortality less than 10% per year for untreated

60. Radiation
• Not curable
• Used for local control
• Some shrink, mostly stops growth
• Local control 90-100% reported

61. Key things to remember:
• Prestyloid vs. retrostyloid
• Pleomorphic most common prestyloid
• Neurogenic tumors are retrostyloid
• “Dumbbell” tumor
• “salt and pepper” appearance
• Most are benign
• Surgery is mainstay of therapy

62. Thank you