GI - Small Bowel Neoplasms And Carcinoid Tumours

Question 1

SB neoplasms: benign tumours

• proportion?
• Name them

Answer 1

• 35% of small bowel neoplasms are benign
• Can affect any element of the small bowel
• Lipoma, leiomyoma, neurofibromas, haemangioma, andenomatous polyps (FAP, Petunia-Jeghers)

Question 2

SB neoplasms: malignant

-name them

Answer 2

• 65% of SB neoplasms are malignant but only form 2% of GI malignancies (ie SB neoplasms are very rare)
• Adenocarcinoma (40% of malignant tumours)
• Carcinoid (40%)
• Lymphoma (especially associated with coeliac disease)
• GIST

Question 3

SB neoplasms: presentation

Answer 3

• often non-specific symptoms so present late
• Nausea and vomiting/obstruction
• Wt loss (unintentional) and abdo pain
• anaemia
• jaundice (from biliary obstruction or liver mets)
• change in bowel habits
• bloating

Question 4

SB neoplasms: imaging and other Ix

Answer 4

• AXR: SBO
• Ba follow through
• CT
• Endoscopy

Question 5

Carcinoid tumours: pathology- embryonic origins

Answer 5

• Diverse group of neuro-endocrine tumours of enterochromaffin cell origin caparable of producing 5HT
• May be derived from: (a) foregut (resp tract), (b) midgut (duodenum, ileum and appendix, (c) hindgut (colorectum)

Question 6

Carcinoid tumours: pathology - what can they secrete?

Answer 6

• 5HT, VIP, gastric, glucagon, insulin, ACTH

* hindgut tumours rarely secrete 5HT

Question 7

What is carcinoid syndrome associated with?

Answer 7

• Carcinoid syndrome suggests bypass of first-pass metabolism and is strongly associated with metastatic disease
• Sites: appendix (45%), ileum (30%), colorectum (20%), stomach (10%)

Question 8

Carcinoid tumours: presentation - local

Answer 8

• Appendicitis
• intussusception or obstruction
• abdominal pain

Question 9

Carcinoid tumours: presentation - carcinoid syndrome (5HT)

Answer 9

• Need mets for this to happen
• Flushing: paroxysmal,, upper body +- wheals
• intestinal: diarrhoea
• valve fibrosis: tricuspid regurgitate and pulmonary stenosis
• hepatic involvement: bypassed 1st pass metabolism

-Wheeze: bronchoconstriction

Question 10

Carcinoid tumours: Ix

Answer 10

• Increased 5-HIAA in urine
• Increased plasma chromogranin A
• CT/MRI: find primary

Question 11

Carcinoid tumours: treatment/Rx

Answer 11

• Symptom relief: loperamide

- Curative: resection, give octreotide to avoid carcinoid crisis

Question 12

Carcinoid tumours: Rx for carcinoid crisis

Answer 12

• tumour outgrows blood supply or is handled too much —> leads to massive mediator release
• vasodilation, hypotension, bronchoconstriction, hyperglycaemia
• Rx: high-dose octreotide

Question 13

Carcinoid tumours: prognosis

Answer 13

-median survival is 5-8 years (3 years if mets present)