Small bowel benign tumours

Epidemiology

• Frequency of benign tumours increases from the duodenum to the ileum

Adenoma

• Most common
• Appear to be more common in ileum (50%) than duodenum (20%) or jejunum (30%)
• Pathophysiology
  • See 'adenocarcinoma' page for the adenoma-carcinoma sequence
• Classification
  • Villous
    • High risk of malignant transformation (up to 50%)
    • Coincident colonic adenomas are common
    • Often present with bleeding or obstruction
    • Can be associated with FAP
  • Tubular
    • Lower malignant potential
    • More common in duodenum
    • Usually asymptomatic
  • Brunner's gland adenomas
    • Rare
    • Caused by hyperplasia of the exocrine glands within the proximal duodenal mucosa
    • Can produce symptoms mimicking PUD
    • No malignant potential - don't perform radical resection
    • Symptomatic lesions can be resected endoscopically or surgically
• Presentation
  • Mostly asymptomatic, occurring singly and found at autopsy
• Management
  • Sporadic duodenal adenomas
    • If possible, remove endoscopically unless >4cm, and screen for CRC
    • Need to weigh up risk of malignancy carefully if surgery would be required - EUS can help
    • EMR has a good success rate (but high risk of complications including bleeding, recurrence and perforation)
    • If it recurs after endoscopic resection or continues to change, pancreaticoduodenectomy will be required
  • Surgically remove jejunal/ileal adenomas
  • Familial adenomas in FAP
    • Found in 50-90%, with 5% lifetime risk of adenocarcinoma
    • Use Spigelman classification to direct management
    • Biopsy of all suspicious, villous or >3cm adenomas in addition to random duodenal biopsy specimens
    • High-grade dysplasia, carcinoma in situ, or Spigelman stage IV necessitates pancreaticoduodenectomy/pancreas-preserving duodenectomy

Leiomyoma

• Pathophysiology
  • Single firm grey or white well-defined masses that arise in the submucosal layer
  • Consist of well-differentiated smooth muscle cells
  • Usually enlarge extraluminally
  • Not detected until they outgrow their blood supply, causing central necrosis, ulceration and bleeding into the lumen

Benign stromal tumours

• See separate topics
• 'GIST' under UGIS
• 'Sarcomas'

Lipoma

• Second most common
• Occur in 50-60yo
• Occur mostly in duodenum and ileum
• Arise from either submucosal adipose tissue or serosal fat
• Classified as stromal tumours
• No malignant potential
• Diagnostic low-attenuation appearance on CT
• Present with obstruction, bleeding or (most commonly) as an incidental finding

Hamartoma

• Seen in a/w Peutz-Jeghers- see separate topic
• Can present with intermittent intussusception
• Adenomatous transformation can occur but malignancy is rare
• Resection is limited to the segment of bowel causing symptoms, as cure is not possible and disease is widespread

Haemangioma

• Developmental malformations consisting of submucosal proliferation of blood vessels
• Can occur anywhere in GIT; jejunum is the most commonly affected part of the small bowel
• Account for 3-4% of benign tumours
• Multifocal in 60% of patients
  • Can also occur in lung, liver and mucus membranes
• Can occur as part of Osler-Weber-Rendu disease
• Turner syndrome - cavernous haemangiomas of the intestine
• Usually present with bleeding
• Diagnosed by angiography or technetium Tc-99m RBC scanning
• Resection is warranted if suspected based on imaging/clinical findings
• Can usually be identified intra-operatively by transillumination and palpation

Desmoid tumours

• Commonly seen in FAP

Approach

• Mostly asymptomatic
• If symptomatic, more likely to present with slow GIT bleed, not abdo pain
• Consideration of excising includes malignant potential, as well as symptomatology
• Typically err on the side of resecting when found - probably will become symptomatic in the future