Parotid Tumours (24)

Question 1

What is the most common parotid benign swelling?

Answer 1

Pleomorphic adenoma

Question 2

What is the meaning of pleomorphic?

Answer 2

Remarkable histologic diversity

Question 3

Describe pleomorphic adenoma appearance.

Answer 3

Benign tumors that consist of a mixture of ductal (epithelial) and myoepithelial cells, and therefore they show both epithelial and mesenchymal differentiation

Question 4

What are the causes of unilateral parotid swelling?

Answer 4

• Duct obstruction – salivary calculus, external ductal compression
• Neoplasia – benign or malignant
• Infective mumps (although bilateral swelling is more common), parotitis

Question 5

What are the clinical signs of malignant parotid tumours?

Answer 5

• Facial nerve affection
• Rapid increase in size
• Fixity to underlying tissue
• Invasion of the skin
• Skin ulcer
• Presence of associated nodes

Question 6

What are the characteristics of malignant neoplasms?

Answer 6

• More rapid increase in size
• Less differentiation (or lack of differentiation, called anaplasia)
• Tendency to invade surrounding tissues (not respect tissue boundaries)
• Ability to metastasize to distant tissues

Question 7

What are the features of malignant cells?

Answer 7

• Invasion: Malignant cells do not respect tissue boundaries, and can be seen infiltrating or invading into surrounding structures
• Increased mitotic rate: Malignant cells will often have increased numbers of mitoses.
• Differentiation and anaplasia: Malignant cells may become less differentiated and anaplastic, losing their resemblance to the parent tissue. Poorly differentiated and anaplastic cells are associated with more aggressive malignancies.

Question 8

What are the Anaplastic Features?

Answer 8

• Loss of normal tissue architecture: Normal cells are usually arranged in an orderly fashion. Epithelial cells often have polarity, with their nuclei at a specific location. Malignant cells lose this architecture and are arranged haphazardly.
• Pleomorphism: Malignant cells may show a range of shapes and sizes, in contrast to regularly sized normal cells. The nuclei of malignant cells are often very large (often larger than the entirety of a normal cell) and may contain prominent nucleoli.
• Hyperchromatic nuclei: The nuclei of malignant cells typically stain a much darker colour than their normal counterparts.
• High nuclear-cytoplasmic ratio: The nuclei of malignant cells often take up a large part of the cell compared with normal cell nuclei.
• Giant cells: Some malignant cells may coalesce into so-called giant cells, which might contain the genetic material of several smaller cells.

Question 9

What is Anaplasia?

Answer 9

Lack of differentiation (loss of similarity to the mother cell indicate very aggressive tumor)

Question 10

What is the single best test to differentiate between benign and malignant cells?

Answer 10

FNAC

Question 11

What is the difference between cytology and histology?

Answer 11

• Cytology is the study of cellular structure and function
• Histology is the study of tissue under the microscope

Question 12

How to differentiate between carcinoma and lymphoma?

Answer 12

Immunohistochemistry

Carcinoma
- originates epithelial cells (e.g. skin, lung, breast etc)

Lymphoma
- orignates in lymphatic system (e.g lymph nodes, spleen etc)
- Main types Hodgkins & Non-hodgkins

Question 13

How to rule out malignancy intraoperative?

Answer 13

Frozen section – See Peptic Ulcer Disease + Hyperparathyroidism station

Question 13

What are the postoperative complications of parotidectomy?

Answer 13

• 7th CN palsy
• Frey’s Syndrome
• Salivary fistula
• Greater auricular nerve damage -numbness to earlobe

Question 13

After 10 years from parotid tumour resection patient develops neck swelling, cause?

Answer 13

Possible recurrence with metastasis

Question 14

What is Frey’s Syndrome?

Answer 14

Auriculotemporal syndrome: post-operative phenomena following salivary gland surgery resulting in gustatory sweating and facial flushing due to reinnervation of postganglionic fibers to sweat gland and cutaneous blood vessels

Question 15

What is the definition of a high-sensitivity test?

Answer 15

• ensitivity is the ability of a test to correctly classify an individual as ′diseased′ (true positive rate)
• High sensitivity = low number of false negatives

Question 16

What is the definition of a high-specificity test?

Answer 16

• Specificity is the ability of a test to correctly classify an individual as disease-free (true negative rate)
• High specificity = low number of false positives

Question 17

What will you do if you have a needle stick injury during an FNAC?

Answer 17

• The wound should be allowed to bleed under running water and wash with soap
• Assess incident risk
• Assess source patient: Take history if he has a possibility of any blood borne infection, take a blood sample from the patient if high risk after consent
• File an incident report and speak to occupational health for advice
• Document the incident

Question 18

What are the FNAC findings?

1. Langherans giant cell
2. Brown pigmented cell
3. Reed Sternberg cell

Answer 18

• If you find Langerhans giant cell + lymphocytes + necrotic material → granuloma (TB)
• If you find Brown pigmented cell + epithelioid cells → malignant melanoma
• If you find Reed Sternberg cell + lymphoid cell + blast cell → hodgkins lymphoma

Question 19

Types of parotid neoplasms?

Answer 19

Question 19

What are the causes of bilateral parotid swelling?

Answer 19

• Local:
  
  • Mumps
  • Parotitis
  • Sialectasis
  • Sjogren’s
  • Neoplasia
• Systemic:
  
  • Sarcoidosis
  • TB
  • Alcoholism/liver cirrhosis
  • Cushing’s
  • Bulimia Nervosa
• Drugs:
  
  • High estrogen OCP
  • Thiouracil
  • Isoprenaline