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SU19.1-2,SU20.1-2,SU21.1-2 | Face, Mouth, Oropharynx and Salivary Glands — PBL Case

CLINICAL SETTING

Mrs. Lakshmi, a 48-year-old schoolteacher, comes to the surgical clinic because of a painless lump in front of and just below her right ear. She first noticed it about eighteen months ago when it was the size of a pea; it has grown very slowly and is now about 3 cm. It does not hurt, has never become red or hot, and does not change in size with meals. She is otherwise completely well, takes no regular medication, and has no difficulty moving her face.

Trigger 1: The painless parotid lump

On examination there is a smooth, firm, rubbery, mobile swelling in the right parotid region. The overlying skin is normal. When asked to show her teeth, raise her eyebrows and close her eyes tightly, her facial movements are completely symmetrical and full. There is no lymphadenopathy in the neck and no other salivary swelling.

DISCUSSION POINTS

  • Which salivary gland is involved, and how does the location and the surface anatomy help you decide?
  • What does the intact facial nerve function tell you about the likely nature of this lump, and which single anatomical relationship makes facial nerve assessment so important here?
  • What is your leading diagnosis for a painless, rubbery, slowly growing parotid lump with an intact facial nerve, and what is your differential?
Click to reveal Trigger 2: Confirming the diagnosis (discuss previous trigger first!)

Trigger 2: Confirming the diagnosis

Ultrasound confirms a well-defined solid mass in the superficial part of the right parotid. Fine-needle aspiration cytology reports a pleomorphic adenoma. The team discusses how to obtain a tissue diagnosis safely and why certain approaches are avoided.

DISCUSSION POINTS

  • Why is fine-needle aspiration cytology preferred over open incisional biopsy for a parotid mass?
  • What role does imaging play in defining the extent of the tumour and planning surgery?
  • Why is a pleomorphic adenoma never simply enucleated, and what is the operation of choice?
Click to reveal Trigger 3: Surgery and its risks (discuss previous trigger first!)

Trigger 3: Surgery and its risks

Mrs. Lakshmi is listed for a superficial parotidectomy with facial nerve preservation. Before consent, she asks the team what could go wrong with the operation and whether the lump could ever come back or turn into cancer if left alone.

DISCUSSION POINTS

  • How would you explain the main risks of parotid surgery to her, including facial nerve injury and Frey's syndrome?
  • Why does an inadequately removed pleomorphic adenoma recur, and what is the risk of long-term malignant transformation if it is left untreated?
  • How does the management principle for this benign tumour differ from that of a malignant salivary or oral tumour such as oral squamous cell carcinoma?

Group Task Assignments

  • Draw a labelled diagram of the parotid gland showing the course of the facial nerve and the superficial and deep lobes, and annotate where a pleomorphic adenoma typically arises.
  • Prepare a one-page patient information sheet explaining superficial parotidectomy, its benefits and its risks in plain language.
  • Construct a comparison table of pleomorphic adenoma, Warthin's tumour and submandibular sialolithiasis covering typical patient, behaviour of the swelling, key investigation and treatment.

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [SU21.1] Describe the surgical anatomy of the salivary glands, with particular reference to the relationship of the facial nerve to the parotid gland and its division into superficial and deep lobes.
  2. [SU21.1] Outline the clinical presentation and pathology of the common salivary gland disorders, contrasting pleomorphic adenoma, Warthin's tumour and obstructive sialadenitis.
  3. [SU21.2] Enumerate the investigations for a salivary swelling and explain why FNAC is preferred to open biopsy; state the principles of treatment including why pleomorphic adenoma is never enucleated.
  4. [SU20.1] Contrast the management principles of a benign salivary tumour with those of a malignant oral/oropharyngeal squamous cell carcinoma.