Histopathology

Question 1

what are the four main layers of the colon wall (from inner to outer)?

Answer 1

mucosa
submucosa
muscularis externa
adventitia/ serosa

Question 2

what is the mucosa made up of?

Answer 2

simple columnar epithelium (straight tubular colonic glands with many mucus secreting (clear) goblet cells as well as absorptive cells)
lamina propria of loose connective tissue, capillaries, enteric neurones, immune cells)
muscularis mucosa of smooth muscle (which is very thin but very important in identifying if tumour has passed this point)

Question 3

what is the submucosa made of?

Answer 3

loose connective tissue (may be some aggregations of lymphatic tissues there - which is normal)
there is also a nerve network: the (the submucus plexus)

Question 4

what is the muscularis externa (AKA muscularis propria) made of?

Answer 4

smooth muscle layers (one circular and one longitudinal)

in between these muscle layers is the myenteric plexus

Question 5

what is the serosa (adventitia) made of?

Answer 5

loose connective tissue - variable thickness and typically includes adipose tissue, or a serosa consisting of a layer of connective tissue and fat, with an outer covering of epithelium

Question 6

describe what a normal lymph node should look like?

Answer 6

spherical, well-circumscribed, populated by small cells with little cytoplasm (lymphocytes mainly). The spherical areas within the node with a lower density of cells are lymph follicles, mainly with germinal centres.

Question 7

describe what an abnormal lymph node could look like?

Answer 7

not spherical
not well-circumscribed
lack of organisation
cystic spaces with tall, dark, tightly packed cells - these regions are tumour cells which have spread from the adenocarcinoma in the nearby colon

Question 8

what is TNM staging used to help with?

Answer 8

deciding on treatments and evaluating prognosis

Question 9

Tis?

Answer 9

tumour in situ, contained within lamina propria and not broken through muscularis mucosa - cells still in normal site

Question 10

T1?

Answer 10

invaded submucosa, but not muscularis externa

Question 11

T2?

Answer 11

invaded muscularis externa, but not extended beyond it

Question 12

T3?

Answer 12

invaded beyond muscularis externa into the subserosa - but not perforated through the serosa or invaded adjacent tissue

Question 13

T4?

Answer 13

directly invaded other organs or perforated the visceral peritoneum

Question 14

NX?

Answer 14

lymph nodes cannot be assessed

Question 15

N0?

Answer 15

no regional lymph node metastasis

Question 16

N1?

Answer 16

metastasis to 1-3 nearby lymph nodes

Question 17

N2?

Answer 17

metastasis in 4 or more regional nodes

Question 18

M0?

Answer 18

no metastasis

Question 19

M1?

Answer 19

metastasis to distant tissues (including distant lymph nodes)

Question 20

stage 1?

Answer 20

T1/2. N0, M0

Question 21

stage 2A?

Answer 21

T3, N0, M0

Question 22

stage 2B?

Answer 22

T4, N0, M0

Question 23

stage 3A?

Answer 23

T1/2, N, M0

Question 24

stage 3B?

Answer 24

T3/4, N1, M0

Question 25

stage 3C?

Answer 25

any T, N2, M1

Question 26

stage 4?

Answer 26

any T, any N, M1