eBook Chapter 7 - Pathology of Cancer

Question 1

Why is cancer pathology important?

Answer 1

• it explains how cancers present clinically
• histopahtoligcal assesmnet importnat for diagnosis, prognosis and threaten
• pathology is a bridge between basic science and clinical medicine

Question 2

In what four ways can we classify tumours/

Answer 2

• behavioural
• histogenetic
• histological
• functional

Question 3

Describe how we classify tumours based on their behaviour

Answer 3

• can be classified as benign or malignant according to their behaviour
• the essential difference is local invasion into surrounding tissue and spread to distant sites - metasiss
• We use TNM staging

Question 4

What is meant by the term staging?

Answer 4

• used to describe the extent of spread of a malignant neoplasm
• TNM is a commonly used generic staging tool

Question 5

What is the staging tool used for colon cancer?

Answer 5

Dukes

Question 6

Why is staging important?

Answer 6

• predicting prognosis and thus also has implications for determining therapeutic options (e.g. local resection vs chemotherapy/radiotherapy)

Question 7

Describe how we classify tumours histogenetically

Answer 7

• classification of neoplasms according to tissue of origin (e.g. eptihaliel, mesenchymal)
• the term differentiation is used to describe the degree to which a neoplasm histologically resembles its tissue of origin
• benign tumours are always well-differnetiated
• grading has implications for prognosis and treatment

Question 8

What is meant by grading?

Answer 8

• describes the degree of differentiation
  1 = well differentiated
  2 = moderately differentiated
  3 = poorly differentiated

Question 9

What is meant by the term anaplastic?

Answer 9

• some malignant tumours are so poorly-differentiated that it is impossible to determine their histiogeneis s

Question 10

How can we classify tumours histologically?

Answer 10

• many tumours can be further classified according to special histological characteristics e.g. thyroid adenocarcinoma
• papillary, follicular, anaplastic

Question 11

How can we classify tumours functionally?

Answer 11

• some may be classified according to a substance or substances produced
• especially endocrine tumours, which secrete functionally active hormones
• e.g. pancreatic islet cell tumours, pituitary tumours

Question 12

What are teratomas?

Where do they usually occur?

Answer 12

• tumours derived from embryonic germ cells which have the capacity to form representatives of all 3 germ cell layers
• usually occur in ovary = benign, testis = malignant, midline structures = behaviour variable (retroperiotonem, mediastinum)

Question 13

What are embryonic tumours?

Answer 13

• represent neoplastic transformation occurring in the developing organ, they are derived form multi portent embryonic blast cells and are give the suffix blastoma
• the majority present at or soon after both , they are the commenest cause of neopplasmsa in childhood and are highly malignant

Question 14

What are hamartomas?

Answer 14

• not genuine neoplasm but tumour-like malformations
• many are present at birth and stop growing when the host stops growing
• examples include pigmented skin naevi and haemangiomas

Question 15

What are the 3 specimens obtained for pathological assessment? Give examples

Answer 15

1. biopsies
   - endoscopic, needle, punch
2. cytology specimens
   - smear, endoscopic brushings, body fluids, FNA
3. surgical resection specimens

Question 16

Describe the macroscopic assessment of tumour resected specimens

Answer 16

• size
• shape (well-circumscribed or irregular)
• extend of local spread
• proximity to surgical resections margins
• identification of lymph nodes (important for staging)
• other macroscopic features were relevant e..g colour, haemorrhage, necrosis

Question 17

What are features are assessed microscopically for tumour resected specimens?

Answer 17

• historical type e.g. glandular, squamous
• degree of differentiation (grading)
• frequency of mitosis
• local invasion