1. BENIGN NEOPLASMS
Gastro-intestinal stromal tumours (GIST)
- Most common benign tumour
- Unlike most other GIT tumours GISTs are non-epithelial
- Arise from intestinal cell of Cajal
- Show c-kit mutation
- Express the CD117 and CD34
- Mostly found in the stomach, jejunum, ileum (rare in the duodenum)
- Grow intramurally – can cause obstruction
- Can outgrow blood supply
- Treatment is via surgical resection
Adenomas
- Benign tumour of glandular origin
- 3 types – true, villous, Brunner gland adenomas
- True and villous type are premalignant
- Most common in ileum, jejunum, duodenum
- Commonly present with bleeding and obstruction
Types
- Brunner gland adenoma
- Benign hyperplastic tumour in duodenum. No malignant potential
- Bleeding is the usual presentation
- Treatment – endoscopic resection
- Villous adenoma
- Most common in periampullary region – presents as obstructive jaundice and upper abdominal pain
- High malignant potential – especially with adenomas >3cm
- Treatment – ERCP to relieve obstruction; panreaticoduodenectomy
- True adenomas
- Usually occurs as a single adeoma
- Treatment – endoscopic excision or pancreaticoduodenectomy depending on invasiveness
- Familial adenomas
- Associated with familial adenomatous polyposis (FAP) – 5% risk of adenocarcinoma
- It is diffuse throughout the duodenum
- Screening endoscopy is done every year
- Treatment
- Endoscopic/open polypectomy – for benign lesions
- Pancreaticoduodenectomy – for high grade lesions or carcinoma in situ
Lipomas
- Benign tumour of fatty tissue
- Most common in ileum – located intramurally in submucosa
- Mostly seen in elderly men
- Can cause intussusception, obstruction or bleeding
- No malignant potential
Peutz-Jegher’s syndrome
- Autosomal dominant condition, characterised by benign hamartomatous polyps in the GIT and hyperpigmented macules on the lips and oral mucosa
- Hyperpigmented lesions can also occur on forearms, palms, soles, digits
- Clinical features – colicky abdominal pain; intussusception, bleeding, anaemia
- Increased risk of developing cancer of the small intestine, stomach, pancreas, ovary, lung, uterus and breast
- Treatment – small resection for removal
Hemangioma
- Usually occur as multiple benign tumours
- They are abnormal submucosal proliferative vessels – most common in the jejunum
- Presents as intestinal bleeding
- Treatment – endoscopic sclerotherapy; angiographic embolisation; resection of bowel segment
2. MALIGNANT TUMOURS
Adenocarcinoma
- Most common in the duodenum and jejunum
- Risk factors – FAP, adenomas, Crohn’s disease, Peutz-Jegher’s syndrome
- Spreads to lymph nodes, liver and peritoneal cavity
- Clinical features – colicky abdominal pain, nausea and vomiting, weight los, occult bleeding, obstruction, jaundice
- Treatment – surgical resection
- Pancreaticoduodenectomy for periampullary/duodenal tumours
- Radical resection for ileal/jejunal tumours
- Right hemicolectomy for terminal ileum tumours
- Poor prognosis for carcinoma patients who previously had Crohn’s Disease
Carcinoid tumours
- Arise from entero-chromaffin cells of crypts of Leiberkuhn
- Commonly occur in the appendix, ileum and rectum
- Extra-intestinal sites – pancreas, biliary tract, bronchus
- 75% of cases are asymptomatic and are found incidentally
- Treatment – surgical resection
3 types
- Foregut tumours – bronchial, stomach, biliary tree
- Secrete low levels of serotonin, but can secrete ACTH
- Midgut – jejunum, ileum, appendix, right colon
- Secrete high level of serotonin
- Hindgut – left colon, rectum
- Secrete somatostatin
Clinical features
- Can be asymptomatic or can present with abdominal pain, intestinal obstruction, diarrhoea
- Carcinoid syndrome – occurs after the carcinoid tumour has metastasised
- Secretion of serotonin, prostaglandins, histamine, kinins – causes flushing, diarrhoea, cyanosis, wheezing, palpitations
- Characteristically exacerbated by alcohol
Non-Hodgkin’s Lymphoma
- GIT is the most common extra-nodal site of NHL MALT, centrocytic, Mediterranean, Burkit type, T-cell
- B cell type is the most common; however, T cell type has worse prognosis
- Clinical features
- Acute – obstruction, perforation; can lead to peritonitis
- Chronic – malaise, weight loss, diarrhoea, abdominal mass
- Treatment – resection followed by adjuvant chemotherapy
Gastro-intestinal stromal tumour (GIST)
- Most are benign but can become malignant
- Large tumours and tumours with high mitotic index have a higher malignant potential
- Clinical features – bleeding (melena), abdominal pain, weakness, weight loss, obstruction or perforation
- Treatment – don’t respond well to radio/chemotherapy, so treatment is excision