Manual of Surgery Sumit Chhikara, Anupam Kumar Singh, Sandeep Kumar Thakur, Pardeep Gupta
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Parotid Swellings1

 
ANATOMY
The parotid gland lies over the mandible and masseter.
It extends from the mastoid process and sternomastoid posteriorly to the posterior border of the ramus of mandible anteriorly.
It is bounded above by the zygomatic arch and below by the posterior belly of digastric.
The secretions of parotid gland reach the mouth by way of the Stenson's duct opening in the mucosa of the mouth opposite the 2nd molar.
The gland is covered by 2 layers of capsule. The true capsule is formed by the condensation of fibrous stroma of the gland. On its outside is the false capsule which is formed by the investing layer of deep cervical fascia.
 
Important Structures in Relation to the Gland (Fig. 1.1)
Facial nerve—It enters the gland at its posteromedial surface near the styloid. In the substance of the gland the nerve divides and rejoins to form a plexus called pes anserinus. Finally it gives off 5 branches, viz.
  • Temporal
  • Zygomatic
  • Buccal
  • Mandibular
  • Cervical
    • Retromandibular vein
    • External carotid artery
      It gives off the following branches within the gland:
      • Posterior auricular artery
      • Maxillary artery
      • Transverse facial artery.
2
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Fig. 1.1: Important structure in relations of parotid gland
 
Causes of Parotid Swelling
  1. Parotitis
    • Mumps
    • Postoperative and debilitated patients
    • Chronic recurrent
    • Calculi
    • Bacterial infection.
  2. Tumours
    • Non-epithelial tumours
  3. Mikulicz's syndrome
    • Sarcoid
    • Reticulosis
    • Sjögren's syndrome
3
 
Clinical Features of Parotitis
  • Swelling
  • Pain: The pain is usually severe due to the presence of the parotid fascia.
  • Opening of Stenson's duct is inflamed and pus may be expressed on gentle compression.
  • Fluctuation is a late feature and should not be allowed to appear.
 
Tumours
Under the international classification, tumours of the parotid are basically of two types:
  • Epithelial
  • Non-epithelial.
 
Epithelial Tumours
  • Adenoma
    • Pleomorphic adenoma
    • Monomorphic adenoma
      • # Adenolymphoma
      • # Oncocytoma
      • # Other types
  • Mucoepidermoid tumours
  • Acinic cell tumour
  • Carcinoma.
 
Non-epithelial Tumours
  • Sarcoma
  • Lipoma
  • Neurofibroma
  • Lymphoma
  • Lymphangioma.
 
Pleomorphic Adenoma
  • Seen more commonly in females greater than 40 years of age.
  • It consists of epithelial cells in the form of acini or cords alongwith myoepithelial cells which are in sheets.4
  • It produces mucoid material which gives the tissue the appearance of cartilage on histological section, hence the name.
  • It is a painless, slow growing swelling.
  • Malignant change is seen commonly. It should be suspected when there is:
    • Pain
    • Rapid growth
    • Lymphadenopathy
    • VII nerve palsy
    • Change in consistency.
 
Adenolymphoma
  • It is a benign tumor and second most common parotid tumour.
  • It constitutes 10% of all parotid tumours.
  • It has double layered eosinophilic epithelium.
  • Lymphatic tissue can be seen in stroma.
  • More common in males.
  • May be multiple.
  • Smooth, soft and cystic tumour.
  • Gives a hot spot in 99mTc scan.
zoom view
Fig. 1.2: Transverse section
 
HISTORY
  • Age
  • Sex5
  • Duration of presence of lump
  • When was it first noticed?
  • Whether associated with pain? Nature of pain
  • Progress of swelling
  • History of trauma or operations
  • History of fever with or without chills and rigors.
  • Presence of other swellings
  • Any change in character of swelling
  • Past history—whether swelling appeared previously?
 
EXAMINATION
 
GPE
  • Temperature
  • Lymphadenopathy.
 
Local Examination
 
Inspection
  • Location
  • Size
  • Shape
  • Ear lobule raised or not?
  • Retromandibular groove absent or present?
  • Overlying skin
  • Opening of parotid duct.
 
Palpation
  • Skin overlying swelling
    • Fixed or not
    • Inflamed or not
  • Tender swelling
  • Surface–smooth or nodular
  • Consistency
    • Rubbery or firm–pleomorphic adenoma
    • Soft, cystic adenolymphoma
    • Hard carcinoma
    • Compress duct orifice
      • # Pus
      • # Parotitis6
    • Palpate regional lymph nodes
    • Relation with relaxed and tightened masseter
    • Facial nerve functions
    • Movement of jaw at temporomandibular joint.
 
INVESTIGATIONS
  • Biopsy is not usually indicated for fear of
    • injury to facial nerve
    • transfer of tumour cells to subcutaneous plane.
  • FNAC—to confirm histological diagnosis and rule out malignant growth.
  • 99mTc-pertechnetate scan—a hot spot can be seen adenolymphoma.
  • FNAC of palpable neck lymph nodes.
  • X-ray mandible and mastoid for bone resorption.
  • CT scan may be required in tumours with their origin in the deep lobe.
 
Differential Diagnosis of Parotid Swelling
  1. Parotid lesion
  2. Sebaceous cyst—presence of puncture and size variations
  3. Lipoma—mobile over taut muscle, slip sign positive.
    Transillumination may be positive.
  4. Lymph node—multiple small swellings.
  5. Adamantinoma—eggshell crackling, soap bubble appearance on X-ray.
  6. Neuroma of facial nerve
  7. Pre-auricular lymphadenitis
    • Retromandibular groove not obliterated
    • Mobile swelling
  8. Fibroma
  9. Branchial cyst—cholesterol crystals on FNAC.
 
TREATMENT
 
Parotitis
Conservative It is done when abscess has not set in, i.e. in the stage of cellulitis.
  • Hydration should be maintained.7
  • Maintain oral hygiene—mouthwash with KMnO4 solution.
  • Antibiotics-cloxacillin 500 mg QID, metronidazole 400 mg TDS.
Operative Abscess needs to be drained before fluctuation sets in:
  • vertical incision is given in front of tragus under general anaesthesia.
 
Pleomorphic Adenoma
 
Benign
Conservative superficial parotidectomy. Here all the gland superficial to the facial nerve is removed.
Enucleation is not done as there may be recurrences.
 
Malignant
  • Radical parotidectomy
    • Structures removed:
      • # Both lobes of parotid
      • # Facial nerve
      • # Parotid duct
      • # Masseter
      • # Pterygoids
      • # Buccinator
      • # Radical block dissection of the neck.
Radiotherapy may be needed although has a poor response rate.
 
Adenolymphoma
Enucleation is the method of choice.