1. Small bowel neoplasms are rare, comprising about 1-2% of gastrointestinal tumors. The most common benign tumors are leiomyomas, adenomas, and gastrointestinal stromal tumors (GISTs), while the most common malignant tumor is adenocarcinoma. 2. Risk factors for small bowel tumors include Crohn's disease, familial polyposis syndromes, and Peutz-Jeghers syndrome. Diagnosis is often difficult but can involve imaging like CT, capsule endoscopy, or surgical exploration. 3. Treatment depends on whether the tumor is benign or malignant and its size and location. Resection is often curative for localized benign and malignant tumors, while

1. Small bowel neoplasms
Dr nawin kumar

2. General Considerations
• Small bowel neoplasms are exceedingly rare
– 80% of the total length
– 5% of all GIT neoplasms
– 1% - 2% of all malignant tumors of the GIT
• factors
– rapid transit of luminal contents;
– high turnover rate epithelial cells
– alkalinity of small intestinal contents;
– the high level of IgA in the intestinal wall
– low bacterial count.

3. • equally distributed between men and women
• age - old
• geographic distribution-
– highest cancer rates found among the Maori of
New Zealand and ethnic Hawaiians.
– low in India, Romania

4. • most benign neoplasms are asymptomatic
• found as an incidental finding.
• Benign
– Leiomyomas and adenomas are the most frequent
– more common in the distal small bowel
– per unit area, duodenal tumors are most frequent.
• most common malignant neoplasm.
– adenocarcinoma
– carcinoid tumor
• site
– Adenocarcinomas - proximal small bowel,
– other malignant lesions - in the distal intestine

5. • risk
– Crohn's disease
– familial adenomatous polyposis
– hereditary nonpolyposis colorectal cancer (HNPCC)
– Peutz-Jeghers syndrome,
– gluten-sensitive enteropathy (i.e., celiac sprue),
– biliary diversion (e.g., previous cholecystectomy).
• Controversial factors –
– smoking,
– heavy alcohol consumption
– red meat
– salt-cured foods.

6. Diagnosis
• Plain films – obstruction
• Angiography is - tumors of vascular origin.
• CT –
– extraluminal tumors such as (GISTs)
– staging of malignant cancers
• Ultrasonography not proved to be effective
• Barium follow through
• CT enteroclysis
• Flexible -duodenal lesions
• colonoscope - terminal ileum
• Push enteroscopy
• radiotelemetry capsules (e.g., capsule endoscopy)
• surgical exploration

7. Benign Neoplasms
• most common
– benign GISTs- most common that produce
symptoms
– adenomas- most common in autopsy
– lipomas.

8. Clinical Manifestations
• Most patients asymptomatic
• often nonspecific
– dyspepsia,
– anorexia,
– malaise,
– dull abdominal pain (often intermittent and
colicky).

9. Treatment
• risk for subsequent complications
– obstruction – intussusceptions
– Hemorrhage - usually occult; hematochezia or
hematemesis may occur
– For final diagnosis - microscopic evaluation.
• polypectomy
• Segmental resection and primary anastomosis
• very small lesions- enterotomy.
• entire small bowel searched - multiple.
• pancreaticoduodenectomy

10. GISTs
• arise from the interstitial cell of Cajal,
• intestinal pacemaker cell of mesodermal
descent.
• incidence is equal in men and in women,
• age - fifth decade of life

11. • intramurally - obstruction.
• extramural growth-
– achieving considerable size
– outgrowing their blood supply –
• ischaemic pain,
• bleeding

12. • Grossly,
– firm, gray-white
– whorled appearance on cut surface;
• microscopic examination
– well-differentiated smooth muscle cells.
– spindle (70%) and epithelioid (30%) cells,
– Most (>90%) GISTs express CD117,
– c-kit proto-oncogene transmembrane protein
– receptor for the stem cell growth factor,
– 70% to 80% express CD34, the human progenitor cell
antigen;
– Sometime actin and desmin

13. Adenomas
• 15% of all benign small bowel tumors
• Most common as asymptomatic
• three primary types:
– true adenomas,
– villous adenomas
– Brunner gland adenomas.
• Site
– 20%- duodenum,
– 30% - jejunum,
– 50% - ileum.

14. • Villous adenomas
– rare
– most commonly - duodenum,
– may be with FAP
– propensity for malignant degeneration
• Brunner gland adenomas –
– produce symptoms mimicking those of peptic
ulcer disease.

15. Lipomas
• Usually- single intramural lesions located in
the submucosa.
• intusception

16. Hamartomas of the small bowel
• as part of the Peutz-Jeghers syndrome,
• an inherited syndrome of mucocutaneous
melanotic pigmentation and gastrointestinal
polyps.
• The pattern of inheritance is simple mendelian
dominant with a high degree of penetrance

17. • classic pigmented lesions
– small, 1- to 2-mm,
– brown or black spots
– location
• circumoral region of the face, buccal mucosa,
• forearms, palms, soles, digits,
• perianal area.
• entire jejunum and ileum
– may rectal and colonic lesions, gastric lesions.

18. • symptom
– most common- colicky abdominal pain-
intermittent intussusception.
– Hemorrhage –
• Frank- autoamputation of the polyps
• anemia.
• Extracolonic cancers are common- small
intestine

19. • treatment –
– directed to presentation
– limited resection.
– widespread nature of intestinal involvement, cure
is not possible

20. Hemangiomas
• developmental malformations
• submucosal proliferation of blood vessels.
• Jejunum - most commonly affected but can involve any GIT
• Rare
• multiple in 60% of patients.
• may occur as part
– Osler-Weber-Rendu disease.
– Turner's syndrome
• Angiography and 99mTc–red blood cell scanning are the
most useful diagnostic studies.
• intraoperative transillumination and palpation
• Segmental resection

21. Malignant
• Carcinoid tumors
• may arise in organs derived from the foregut,
midgut, and hindgut.
• upto 80% of carcinoids are asymptomatic and
found incidentally
• more than 90% in three sites:
– the appendix (45%),
– the ileum (28%), and
– the rectum (16%)
AIR

22. • The malignant potential (ability to metastasize) is
related to
• location,
– Only 3% of appendiceal carcinoids metastasize,
– but 35% of ileal carcinoids gets metastasis
• size,
– <1 cm in diameter- 2% metastasis. In contrast,
– 1 to 2 cm in diameter 50% metastasis
– > 2 cm in diameter 90% metastasis
• depth of invasion,
• growth pattern

23. • Grossly
– small, firm submucosal nodules
– multicentric in 20% to 30%
– usually yellow on cut surface
• grow very slowly,
• after invasion of the serosa-
• intense desmoplastic reaction producing mesenteric
fibrosis, intestinal kinking, and intermittent obstruction.
Small bowel carcinoids are of patients.
• frequent coexistence of a second primary malignant
synchronous adenocarcinoma
• associated with MEN 1 in about 10% of cases.

24. • Clinical Manifestations
– Local symptom- similar to other small bowel
tumors
– carcinoid syndrome

25. • Malignant Carcinoid Syndrome
• relatively rare disease < 10% of patients
• humoral factors
– serotonin,
– 5-hydroxytryptophan (a precursor of serotonin synthesis),
– histamine,
– dopamine,
– kallikrein,
– substance P,
– prostaglandin,
– neuropeptide K

26. • requirement
– massive hepatic replacement by metastatic disease.
– bypass the liver, specifically ovarian and retroperitoneal
carcinoids,
• includes
– vasomotor-
• cutaneous flushing
• asthma
– cardiac,
• pulmonary stenosis
• tricuspid insufficiency
• tricuspid stenosis
– gastrointestinal manifestations.
• diarrhea (76%);
• hepatomegaly

27. • Cutaneous flushing - four varieties:
• diffuse erythematous,
– short lived
– normally affects the face, neck, and upper chest;
• violaceous,
– similar to diffuse erythematous flush
– attacks may be longer
– patients may develop a permanent cyanotic flush with watery eyes and
injected conjunctivae;
• prolonged flushes,
– last up to 2 to 3 days
– involve the entire body
– profuse lacrimation, hypotension, and facial edema;
• bright-red patchy flushing,
– which is typically seen with gastric carcinoids.
• diarrhea
– episodic (usually occurring after meals),
– watery, and often explosive

28. • Diagnosis
• various humoral factors
– urinary levels of 5-HIAA measured over 24 hours
• serotonin -liver and lung -inactive 5-hydroxyindoleacetic
– plasma concentrations of chromogranin A
– Plasma serotonin, substance P, neurotensin, neurokinin A, and
neuropeptide K
• Provocative tests using pentagastrin, calcium, or epinephrine may
be used to reproduce the symptoms of carcinoid tumors.
• Barium radiographic studies –
• multiple filling defects - kinking and fibrosis of the bowel
• Angiography
• high-resolution ultrasonography
• somatostatin receptor scintigraphy using 111In-labeled
pentetreotide.

29. Treatment
• based on
– tumor size and site
– presence or absence of metastatic disease
• <1 cm + no metastasis- a segmental intestinal
resection
• > 1 cm, with multiple tumors + metastasis, -wide
excision of bowel and mesentery is required.
• Lesions of the terminal ileum - right
hemicolectomy.
• duodenal - pancreaticoduodenectomy.

30. • metastatic disease- surgical debulking,
• hepatic metastases-
– wedge resection or formal hepatic lobectomy.
– hepatic artery ligation or percutaneous
embolization

31. • Medical therapy -relief of symptoms caused by
the excess production of humoral factors.
• analogues of somatostatin, such as octreotide
• Interferon-α
• Serotonin receptor antagonists –
– Methysergide - retroperitoneal fibrosis.
– Ketanserin and cyproheptadine
• Cytotoxic chemotherapy -limited success.
– streptozotocin and 5-fluorouracil or
cyclophosphamide

32. • Prognosis
• Carcinoid tumors have the best prognosis of
all small bowel tumors,
– Resection of a carcinoid tumor localized - 100%
survival rate.
– Five-year survival rates are about 65% among
patients with regional disease and
– 25% to 35% among those with distant metastasis

33. • carcinoid crisis during anaesthesia
– hypotension,
– bronchospasm,
– flushing,
– tachycardia to arrhythmias.
• The treatment - IV octreotide, antihistamine,
hydrocortisone