Stomach: NET

Question 1

What are the two major types of neuroendocrine gastroenteropancreatic tumours (GEP-NETs)?

Answer 1

Intestinal NET (carcinoid) and Pancreatic NET

Intestinal NETs account for 2/3 of cases, while Pancreatic NETs account for 1/3.

Question 2

What percentage of all gastric tumours do gastric carcinoids represent?

Answer 2

2%

Gastric carcinoids are a small fraction of gastric tumours.

Question 3

What is the most common site for carcinoid tumours?

Answer 3

Appendix, rectum, ileum, stomach

The appendix accounts for 48%, rectum 17%, ileum 12%, and stomach 9%.

Question 4

What marker is commonly contained in neuroendocrine tumours?

Answer 4

Chromogranin A

This marker is important for diagnosis.

Question 5

From which cells do gastric carcinoids arise?

Answer 5

Histamine containing enterochromaffin-like cells (ECL)

These cells are found in the fundus and body of the stomach.

Question 6

What stimulates gastric acid secretion?

Answer 6

Gastrin and histamine

Gastrin is produced by G cells, and histamine is secreted by ECL cells.

Question 7

What role does somatostatin (SST) play in gastric acid secretion?

Answer 7

Inhibits gastrin and histamine production

SST is produced by D cells and provides negative feedback.

Question 8

What condition can lead to increased gastrin and ECL cell stimulation?

Answer 8

Chronic atrophic gastritis

This condition reduces acid production, leading to reduced SST.

Question 9

What are common symptoms of atypical carcinoid syndrome?

Answer 9

Patchy cutaneous flushing, watery eyes, bronchospasm, headaches

These symptoms are due to increased histamine release.

Question 10

What are the classical symptoms of carcinoid syndrome?

Answer 10

Flushing, bronchospasm, diarrhoea

These symptoms are due to serotonin and tachykinins.

Question 11

How is carcinoid diagnosis typically confirmed?

Answer 11

Biopsy with staining for chromogranin A

This staining is crucial for identifying neuroendocrine tumours.

Question 12

What receptors do gastric carcinoids express?

Answer 12

Somatostatin 2 receptors

This allows binding with octreotide for diagnostic purposes.

Question 13

What is Type 1 gastric carcinoid associated with?

Answer 13

Chronic atrophic gastritis

Type 1 is common and usually small and well-differentiated.

Question 14

What is the treatment for Type III gastric carcinoid?

Answer 14

Total gastrectomy with D2 lymphadenectomy

This treatment is indicated if not metastatic.

Question 15

What percentage of gastric carcinoids are classified as Type II?

Answer 15

8%

Type II is rare and occurs with gastrinoma in MEN-1.

Question 16

What is the survival rate for patients with aggressive Type III gastric carcinoid after 5 years?

Answer 16

50%

This indicates a poor prognosis for aggressive forms.

Question 17

Describe type 1 gastric NETS:
- incidence
-risk factor
-histology
-management

Answer 17

-common (75%).
-Associated with chronic atrophic gastritis.
- Usually small, well differentiated.
- If <2cm can be removed endoscopically.
-If >2cm or > 6 polyps or recurrence then resect

Question 18

Describe type 2 gastric NETS:
- incidence
-risk factor

Answer 18

• rare (8%)
• occur with gastrinoma in MEN-1

Question 19

Describe type III gastric NETS:
- incidence
-risk factor
-histology
-management
-Survival

Answer 19

(21%) – aggressive.
Present as large ulcerating solitary mass, sometimes liver mets,
not associated with gastritis, MEN-1 or hypergastrinaemia.
Treat with total gastrectomy with D2 lymphadenectomy if not metastatic.
Survival 50% 5 years