Basic Science Resident Conference

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Basic Science Resident Conference

• Hau Sin Wong
• 1/29/04

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History

• 80 yo male presenting with a painless right neck
  mass
• No weight loss
• Complains of dysphagia and left otalgia
• No facial twitching
• Denies any fevers or night sweats
• Denies any episodes of flushing or palpitations

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• PMHCAD, CHF, Atrial Fibrillation
• PSH hernia repair, pacemaker
• Sh non-smoker, no ETOH abuse
• FH no h/o cancer
• PE
• Ears tm clear bilaterally
• nose no mass
• OC/OP right tonsillar assymetry
• Neck firm 2cm mass at the angle of the
  mandible-fixed
• CN II-XII intact

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Parapharyngeal Space

• Anatomy inverted pyramid
• Boundaries
• Superiorly-skull base
• Inferiorly- hyoid bone
• Anteriorly Pterygomandibular fascia
• Posteriorly Prevertebral fascia
• Medially Pharyngobasilar fascia
• Laterally ramus of the mandible and
  posterior digastric

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• Prestyloid space
• Located in the anterolateral 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

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Parapharyngeal Space
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Parapharyngeal Space Tumors

• Account for less than 1 of head and neck cancers
• 80 are benign and 20 are malignant
• Further separated into the prestyloid and
  poststyloid space which is important in
  predicting the histology of the tumor

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Prestyoid space

• 40-50 are salivary gland neoplasms
• 80-90 are benign- pleomorphic adenoma
• 20 are malignant- acinic cell carcinoma and
  carcinoma ex pleomorphic adenoma
• Major vessels are displaced posteriorly and
  parapharyngeal fat pad displaced medially

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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

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Differntial Diagnosis

• Salivary Neoplasms
• Neurogenic Neoplasms
• Lymphoreticular lesions
• Miscellaneous

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Diagnostic Studies

• CBC, pre-op labs, urine metanephrine
• Imaging CT Neck, MRI, angiography

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• Pleomorphic Adenoma
• Histology
• Mixture of epithelial, myopeithelial and stromal
  components
• Epithelial cells nests, sheets, ducts,
  trabeculae
• Stroma myxoid, chrondroid, fibroid, osteoid
• No true capsule
• Tumor pseudopods

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Treatment

• Mainly surgical excision
• Radiation therapy and chemotherapy mainly for
  poor surgical candidates, unresectability, fail
  balloon occlusion test

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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

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Transoral

• Limited view and poor vascular control and risk
  of injury to neurovascular structures
• Not recommended

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Transcervical

• Transverse cervical incision two finger breaths
  below the mandible, close to the hyoid
• Raise subplatysmal flaps and retract digastric
  muscle and possibly the submandibular gland. Gain
  access to the carotid and internal jugular

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Transparotid

• Employed for lesions in the deep lobe of the
  parotid
• Perform a superficial parotidectomy, dissect and
  elevated facial nerve then remove deep lobe

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Transmandible/transcervical

• Mandibulotomy approach provides access to the
  poststyoid and superior parapharyngeal space with
  control of the carotid and internal jugular
• Indicated for vascular lesions that extend to the
  superior aspect of PPS, lesions that surround the
  great vessels, lesions greater than 8cm

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Transmastoid/transcervical access to the
jugular foramen after cortical mastoidectomy and
removal of the mastoid tip. Utilized to resect
glomus vagale and jugulare tumorsInfratemporal
fossa utilized for large tumors extending into
the superior aspect of the PPS and possible
intracranial extension
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Conclusion

• Parapharyngeal space is a potential space defined
  as an inverted pyramid
• Accounts for lt1 of head and neck neoplasms
• Distinguished into pre and postsytoid spaces
  which help determine etiology of the lesion
• Majority are benign