GIT

• Small bowel tumours


  Rare neoplasms, 3% of all GI tumours
• Small bowel tumours


  • Common in elderly men
  • Common in New Zealand and Hawaii
  • Can be benign or malignant
  • Early diagnosis is difficult
  • Presentations are vague initially

  
• Even though 80% total length and 90% of mucosal surface area of the GIT is small bowel, small bowel tumours are rare
• Reasons why malignancy is uncommon in the small bowel

  • Rapid transit time, 30 minute to 2 hours
  • Alkaline mucus rich luminal content is protective
  • Cells of small bowel produce the enzyme benzopyrene hydroxylase which detoxifies the carcinogen—benzopyrone
  • High levels luminal IgA provides immunity
  • Plenty of lymphoid tissue in the wall provides immunity
  • Healthy small bowel has got less bacterial load and so their toxic metabolites (as compared to colon)
• Risk factors for small bowel tumours

  • Bile acids and their metabolites
  • Post-cholecystectomy status
  • Familial adenomatous polyposis (FAP) especially with duodenal adenomas
  • Crohn's disease
  • Chronic immunosuppression
  • Von Recklinghausen's disease of neurofibromatosis
  • Smoking, red meat, alcohol, salt food
• Presentations of small bowel tumours

  • Asymptomatic initially
  • Features of obstruction/intussusception/bleeding
  • Vague abdominal discomfort
• Investigations for small bowel tumours

  • Small bowel enteroclysis
  • CT abdomen
  • CT enteroclysis
  • Video capsule endoscopy
  • CT angiography
  • Enteroscopes (push type or Sonde pull enteroscopes)
  • Intraoperative enteroscopes
• Benign tumours of small bowel

  • Leiomyoma or GIST
  • Adenomas
  • Lipoma
  • Peutz-Jegher's Syndrome
  • Haemangioma

  
• Malignant tumours of small bowel

  • Adenocarcinoma
  • Non-Hodgkin's lymphoma (NHL)
  • Carcinoid tumour
  • GIST
  • Liposarcoma and myxoliposarcoma

  
• Adenocarcinoma


  Most common primary malignant small bowel tumour, 40% of small bowel tumours

  
• Adenocarcinoma


  • 80% cases in the duodenum and jejunum
  • In Crohn's disease, occurs in younger age group and commonly in ileum (70%)
  • Nonspecific features, anorexia, crampy pain abdomen, bleeding and diarrhoea, obstruction or features of metastases (liver)
  • CT scan, capsule endoscopy are the investigations
  • RT and chemotherapy are less beneficial
  • It carries a poor prognosis

  
• Non-Hodgkin's lymphoma (NHL)


  25% of small bowel tumours, GI is the commonest extranodal site of NHL (20%), with small bowel (primary intestinal NHL) as second common site (30%) for extranodal site of NHL
• Non-Hodgkin's lymphoma (NHL)


  • Lymphadenopathy/mediastinal lymph node enlargement are absent, Normal spleen, liver, blood peripheral smear are observed
  • B cell type is the commonest type 75%, common in ileum
  • Presentations are malabsorption, obstruction, perforation, haemorrhage or palpable mass
  • In children lymphomas are the most common intestinal neoplasm
  • 25% of patients develop perforation
  • Fever when present suggests systemic spread
  • CT scan with CT guided biopsy or laparoscopic biopsy is needed
  • Surgical resection and chemotherapy are the treatment
  • Prognosis is poor

  
• Carcinoid tumour


  30% of small bowel tumours, commonly occurs in appendix (45%), ileum (25%) and rectum (15%), 10% of cases are associated with MEN syndrome type I

  
• Carcinoid tumour


  • Most often asymptomatic—an incidental finding
  • May present with abdominal pain, features of intestinal obstruction, diarrhoea
  • Hindgut carcinoids present with constipation, bleeding per rectum, rectal tenesmus
  • Once secondaries develop in the liver Carcinoid syndrome develops

  
• Surgical treatment for carcinoid tumours

  • Appendix: Tip/lesion less than 2 cm but not involving base—appendicectomy, Lesion more than 2 cm/involving base right hemicolectomy
  • Small bowel lesion: Less than 1 cm—segmental resection, More than 1 cm—radical resection with adjacent mesentery, Terminal ileum—right hemicolectomy
  • Rectal lesion: Less than 1 cm—endoscopic resection, 1 cm invasive—wide excision, More than 1 cm—anterior resection

  
• GIST (gastrointestinal stomal tumour)


  Rare but most common nonepithelial small bowel tumours, 25% of GIST occurs in small bowel
• GIST


  • Palpable mass, compression, haemorrhage are the features, has less affinity for lymphatics
  • CT is diagnostic, Histochemistry and tumour markers are needed
  • Surgical wide resection is the treatment
• Other malignant tumours of small bowel

  • Liposarcoma and myxoliposarcoma
  • Secondaries in small bowel (very rare, if present, primary being commonly melanoma)

  
• Classification of polyps/benign tumours of colon

  • Inflammatory: Ulcerative colitis, Segmental colitis, Crohn's disease, Diverticulitis, Dysenteric colitis
  • Hyperplastic (Metaplastic): Also called as metaplastic mucosal polyps
  • Hamartomatous: Peutz-Jegher's syndrome, Juvenile polyp, Cronkhite—Canada syndrome
  • Neoplastic: Tubular—pedunculated, Villous—sessile, Tubulo—villous, FAP—familial adenomatous polyposis
  • Others: Lipoma, haemangioma, leiomyoma

  
• Peutz-Jegher's polyp


  Autosomal dominant disease, common in small intestine (jejunum) but can also occur in large intestine, features are multiple, familial, hamartomatous intestinal polyps, associated with melanosis of the oral mucosa, lips
• Adenoma of colon


  Can be solitary or multiple, sessile or pedunculated, Tubular is commonly 1-2 mm sized and sessile is 3-4 mm sized, It has malignant potential

  
• Factors increasing malignant potential of adenoma

  • Size (>2 cm—30-50% chances of developing carcinoma, 1-2 cm —10% chances of carcinoma, < 1 cm —1-5% chances of carcinoma)
  • Sessile nature
  • Villous architecture
  • Dysplasia

  
• Grading of adenoma


  • Minimal hyperplasia, no cellular atypia
  • Mild hyperplasia, cellular atypia
  • Moderate hyperplasia, cellular atypia
  • Severe hyperplasia, cellular atypia
  • Carcinoma in situ

  
• Features of adenoma


  • Can be asymptomatic
  • Bleeding per anus is usually chronic but rarely can be acute
  • Anaemia
  • Prolapse—common in tubular type
  • Diarrhoea common in villous type; mucus discharge
  • Tenesmus, colicky abdominal pain
  • Poor general health
  • Electrolyte imbalance—hypokalaemia
• Investigations for adenoma


  • Serum electrolytes
  • Barium enema study—shows filling defect—usually multiple
  • Colonoscopy—biopsy is a must, Size should be noted, Texture—harder tumour more likely to be malignant, Colour of the lesion—pale is benign, pink, red and active—could be carcinoma, Ulceration on the surface if it has turned into malignancy

  
• Treatment for adenoma


  • Colonoscopic polypectomy using snare, Any adenoma more than 5 mm in size should be removed colonoscopically
  • Diathermy excision/coagulation with sigmoidoscope
  • Per-anal polypectomy
  • Per-anal excision with clear margin of the rectal sessile adenoma
  • Open-abdominal colotomy and polypectomy in case of huge adenoma
  • Segmental resection of the colon if polyps/adenomas are limited to one segment of the colon confirmed by Colonoscopy
  • Total colectomy/proctocolectomy if multiple polyps present all over colorectum and if associated with FAP
  • Blood transfusions, correction of electrolytes, protein supplements

  
• Problems in therapeutic colonoscopy

  • Perforation due to necrosis
  • Haemorrhage—secondary
  • Intracolonic explosions
  • Sepsis
• Familial adenomatous polyposis (FAP)


  Inherited disorder autosomal dominant (AD) characterized by cancer of the large intestine (colon) and rectum, People with the classic type may begin to develop multiple noncancerous (benign) growths (polyps) in the colon as early as their teenage years

  
• Familial adenomatous polyposis (FAP)


  • Male >female
  • If left untreated, carcinoma develops in 100% of affected patients by the fifth decade
  • Gardner syndrome: desmoid tumour in the abdomen, osteomas (75%) and epidermoid cysts
  • Turcot"s syndrome [FAP + brain tumour (medulloblastoma or gliomas)]

  
• Surgical treatment for colon polyps/adenomas

  1. Limited to one segment of the colon - Partial colectomy

  2. Multiple polyps present all over colorectum and associated with FAP - Total colectomy/proctocolectomy

  
• Supportive treatment for colon polyps/adenomas

  • Blood transfusions
  • Correction of electrolytes
  • Protein supplements
• Problems in therapeutic colonoscopy

  • Perforation due to necrosis
  • Haemorrhage—secondary
  • Intracolonic explosions
  • Sepsis
• Familial adenomatous polyposis (FAP)

  Inherited disorder autosomal dominant (AD) characterized by cancer of the large intestine (colon) and rectum

  
• People with the classic type of familial adenomatous polyposis may begin to develop multiple noncancerous (benign) growths (polyps) in the colon as early as their teenage years

  
• Male > female in FAP
• If left untreated, carcinoma develops in 100% of affected FAP patients by the fifth decade
• Gardner syndrome


  • Desmoid tumour in the abdomen, osteomas (75%) and epidermoid cysts
• Turcot's syndrome


  • FAP + brain tumour (medulloblastoma or gliomas) or sarcoma of bone
• Presenting symptoms of FAP

  • Lower abdominal pain
  • Loose stools with blood and mucus
  • Weight loss