Small bowel neoplasms Dr nawin kumar
May 27, 2015
Small bowel neoplasms
Dr nawin kumar
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.
• 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
• 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
• 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.
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
Benign Neoplasms
• most common – benign GISTs- most common that produce
symptoms– adenomas- most common in autopsy– lipomas.
Clinical Manifestations
• Most patients asymptomatic • often nonspecific – dyspepsia, – anorexia, – malaise, – dull abdominal pain (often intermittent and
colicky).
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
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
• intramurally - obstruction. • extramural growth- – achieving considerable size – outgrowing their blood supply – • ischaemic pain,• bleeding
• 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
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.
• 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.
Lipomas
• Usually- single intramural lesions located in the submucosa.
• intusception
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
• 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.
• symptom – most common- colicky abdominal pain-
intermittent intussusception. – Hemorrhage – • Frank- autoamputation of the polyps• anemia.
• Extracolonic cancers are common- small intestine
• treatment –– directed to presentation– limited resection. – widespread nature of intestinal involvement, cure
is not possible
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
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
• 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
• 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.
• Clinical Manifestations– Local symptom- similar to other small bowel
tumors– carcinoid syndrome
• 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
• 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
• 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
• 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.
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.
• metastatic disease- surgical debulking, • hepatic metastases- – wedge resection or formal hepatic lobectomy. – hepatic artery ligation or percutaneous
embolization
• 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
• 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
• carcinoid crisis during anaesthesia– hypotension,– bronchospasm, – flushing, – tachycardia to arrhythmias.
• The treatment - IV octreotide, antihistamine, hydrocortisone