Solitary Neck Masses


Solitary Neck Masses

  1. Differential Diagnosis
    • includes infectious, congenital, and malignant etiologies
    • age is an important consideration: the majority of isolated neck masses in patients over 40 are malignant

    1. Infectious Masses
      • suspected when a mass develops after a recent upper respiratory or dental infection
      • most of these masses are ‘reactive’ lymph nodes and will resolve within several weeks
      • if the mass is tender to palpation and has overlying erythema and warmth, then a course of antibiotics is indicated (Augmentin, e.g.)
      • if the mass persists or recurs, then an FNA or surgical excision is indicated

    2. Congenital Masses
      • may present in young adults as a soft cystic mass
      • may become infected, often after a URI

      1. Thyroglossal Duct Cysts
        • present as an anterior midline mass between the thyroid gland and hyoid bone
        • protrusion of the tongue results in an upward movement of the mass
        • 1% contain malignancy
        • surgical excision is indicated, which includes the entire tract as well as the central portion of the hyoid bone (Sistrunk procedure)

        Infected Thyroglossal Duct Cyst
        Infected Thyroglossal Duct Cyst

      2. Branchial Cleft Cysts
        • second branchial cleft cysts are the most common (95%) and are located high on the anterior border of the sternocleidomastoid muscle
        • they communicate with the tonsillar fossa and are in close proximity to the carotid sheath
        • first branchial cleft cysts are located below the angle of the mandible and may communicate with the auditory canal
        • third branchial cleft cysts present at the lower aspect of the SCM and communicate with the pharynx or piriform sinus
        • CT scan will define the relevant anatomic relationships between the cranial nerves and other deep structures
        • FNA should be done to exclude malignancy
        • complete excision of the cyst and tract is indicated

        Second Branchial Cleft Cyst
        Second Branchial Cleft Cyst

    3. Malignant Masses
      • excluding malignancy is the chief goal in adult patients with a neck mass
      • a focused history and physical exam can strongly suggest a malignant etiology

      1. History
        • lack of an infectious or congenital etiology
        • duration of the mass > 2 weeks
        • age > 40
        • tobacco and alcohol abuse
        • history of melanoma or head and neck cancer
        • immunocompromised status
        • hoarseness or recent voice change
        • fever, night sweats, weight loss suggest lymphoma

      2. Physical Exam
        • firm, fixed, nontender mass > 1.5 cm
        • a mass at the angle of the jaw is usually a parotid tumor or enlarged node
        • a firm mass along the anterior SCM muscle usually represents a metastatic head and neck or thyroid cancer
        • posterior triangle masses are almost always malignant
        • supraclavicular masses, especially on the left, commonly are from a metastatic abdominal source – Virchow’s node
        • a suspicious pigmented lesion on the scalp, face, or neck suggests a melanoma primary

        Supraclavicular Node (Virchow's Node)
        Supraclavicular Node (Virchow's Node)

      3. Evaluation
        • if the patient likely has a head and neck primary cancer, then a referral to an ENT surgeon is prudent
        • suspicious masses will need to be evaluated with CT or MRI
        • FNA is the first choice for tissue diagnosis
        • if the FNA is nondiagnostic, then a core needle biopsy should be done
        • excisional biopsies are rarely necessary except in cases of lymphoma, where additional tissue may be necessary for subtyping

Salivary Gland Tumors

  1. Anatomy
    1. Parotid Gland
      • divided into 2 lobes by the facial nerve
      • the superficial lobe is anterior to the facial nerve; the deep lobe is posterior to the facial nerve
      • no discrete fascial plane separates the two lobes
      • majority of the gland is contained in the superficial lobe

      Parotid Gland and Facial Nerve
      Relationship of the Facial Nerve and the Parotid Gland

    2. Submandibular Gland
      • lies superficial to the mylohyoid muscle
      • in close proximity to the facial artery and vein

  2. Clinical Presentation
    • most present as painless, slow-growing, well circumscribed masses
    • facial nerve weakness suggests malignancy

  3. Diagnosis
    • CT and MRI are the most sensitive studies to determine soft tissue extension and involvement of adjacent structures
    • FNA is 70% - 80% accurate in establishing a preop diagnosis
    • occasionally an ultrasound-guided core needle biopsy will be necessary

  4. Benign Tumors
    1. Parotid Gland
      • most frequent site of salivary gland tumors
      • majority of parotid gland neoplasms are benign (75%)

      1. Pleomorphic Adenoma
        • most common salivary gland neoplasm
        • contains both epithelial and mesenchymal elements
        • accurately diagnosed by FNA
        • optimal treatment is excision of the superficial lobe with facial nerve preservation
        • enucleation should not be done – incomplete excision and tumor spillage will lead to difficult to resect recurrences

      2. Warthin’s Tumor
        • occurs at the angle of the jaw
        • majority occur in men
        • has a strong association with smoking
        • 10% are bilateral
        • lymphoid tissue origin
        • treatment is superficial parotidectomy

    2. Submandibular Gland
      • only 40% are benign
      • 90% of benign tumors are pleomorphic adenomas

  5. Malignant Tumors
    1. Parotid Gland
      1. Mucoepidermoid Carcinoma
        • most common malignant parotid tumor
        • majority are low-grade lesions with an excellent prognosis

      2. Adenoid Cystic Carcinoma
        • second most common parotid malignancy
        • invades peripheral nerves
        • lymphatic spread is first to the intraparotid nodes, and then to level I and level II cervical nodes
        • distant metastases are common, but lengthy survival is possible

      3. Metastatic Lesions
        • scalp and facial melanomas may frequently metastasize to the intraparotid lymph nodes
        • if there is no distant spread, parotidectomy is indicated

      4. Management
        • superficial parotidectomy with facial nerve preservation is the mainstay of treatment
        • if the tumor extends into the deep lobe, then total parotidectomy with facial nerve preservation is required
        • the facial nerve may be sacrificed if it is encased in tumor, or if it is nonfunctional
        • a selective neck dissection is indicated for palpable adenopathy
        • adjuvant XRT is required for perineural invasion, direct invasion of regional structures, lymph node metastases, or high-grade histology

    2. Submandibular Gland
      1. Management
        • surgery consists of en bloc resection of the gland along with the submental and submandibular lymph nodes
        • tumors that invade the mouth, tongue, or mandible will require radical resection
        • adenopathy mandates a therapeutic neck dissection
        • high risk lesions will require adjuvant XRT

  6. Parotidectomy
    1. Facial Nerve Identification
      • the most challenging part of the operation, and many different approaches have been described
      • key anatomic landmarks include the posterior belly of the digastric muscle, mastoid process, stylohyoid, tragal ‘pointer’ of the cartilaginous external ear canal, and the palpable tympanomastoid suture

      Facial Nerve Landmarks
    2. Complications
      1. Facial Nerve Injury
        • transient paralysis of one or more branches may occur in up to 60% of patients, with the marginal mandibular branch being the most frequently injured
        • the great majority of these injuries resolve within one month, but some can take a year or more
        • known transections should be immediately primarily repaired
        • if a tension-free primary repair can’t be accomplished, then a graft from the greater auricular nerve can be used
        • inability to close the eye can lead to corneal injury and must be treated with eye drops, eye protection, and an ophthalmology consult

      2. Frey’s Syndrome
        • gustatory sweating that develops 1 – 12 months postop
        • characterized by unilateral sweating and flushing of the parotid area skin during meals
        • proposed pathogenesis is that divided parasympathetic fibers from the auriculotemporal nerve reattach to cutaneous sweat glands, which normally have sympathetic innervation
        • Botox injections are the primary treatment

Neck Dissection

  1. Lymphatic Drainage of the Neck
    • divided into 7 levels
    • allows for a standardized format to communicate concerning specific sites within the neck
    • primary tumors in the oral cavity and lip metastasize to levels I, II, and III
    • tumors of the oropharynx and larynx spread to the jugular chain nodes (levels II, III, IV)
    • thyroid malignancies spread to the jugular chain nodes and level V as well as the paratracheal nodes (level VI) and upper mediastinum (level VII)

    Lymphatic Drainage Zones - Neck
  2. Neck Dissection Types
    1. Radical Neck Dissection
      • removes nodal basins I – V
      • also removes the SCM, internal jugular vein, and spinal accessory nerve
      • has largely been replaced by modified radical neck dissection or selective neck dissection

    2. Modified Radical Neck Dissection
      • preserves the SCM, internal jugular vein, and spinal accessory nerve
      • as effective in controlling disease as radical neck dissection, and has an improved functional outcome

    3. Selective Neck Dissection
      • underlying principle is that specific primary sites drain into predictable nodal groups, allowing preservation of noninvolved nodes
      • results in improved functional and cosmetic outcomes
      • supraomohyoid neck dissection removes nodal levels I – III
      • lateral neck dissection removes levels II - IV
      • posterolateral neck dissection removes levels II – V
      • anterior (central) neck dissection removes level VI

      Omohyoid and Lateral Neck Dissections
      Posterolateral and Central Neck Dissections
  3. Potential Nerve Injuries
    1. Marginal Mandibular Nerve
      • most inferior branch of the facial nerve
      • innervates the muscles of the lower lip
      • lies below the angle of the mandible
      • incisions should be made 2 fingerbreadths below the inferior edge of the mandible

      Location of the Marginal Mandibular Nerve
    2. Spinal Accessory Nerve
      • exits the posterior border of the SCM and traverses the posterior triangle to innervate the trapezius
      • is easily injured because it has a superficial course in the posterior triangle
      • injury results in shoulder weakness and chronic pain

      Location of the Spinal Accessory Nerve
    3. Vagus Nerve
      • lies in the carotid sheath posterior to the vessels
      • injury will result in unilateral vocal cord paralysis
      • a nonrecurrent right laryngeal nerve occurs in 1% of patients







References

  1. Schwartz, 10th ed., pgs 595 – 600
  2. Cameron, 13th ed., pgs 840 - 846
  3. UpToDate. Salivary Gland Tumors: Epidemiology, Diagnosis, Evaluation, and Staging. Scott A. Laurie, MD, FRCPC. Feb 04, 2020. Pgs 1 – 22
  4. UpToDate. Evaluation of a Neck mass in Adults. Daniel G. Deschler, MD, FACS, Joseph Zenga, MD. Oct 11, 2019. Pgs 1 – 28
  5. StatPearls [Internet]. Parotidectomy. Youssef El Sayed Ahmad, Ryan Winters. July 31, 2020
  6. Treatment of Complications of Parotid Gland Surgery. R. Marchese-Ragona, C. De Filippis, and A. Staffieri. Acta Otorhinolaryngol Ital. 2005 Jun; 25(3): 174 – 178