Tumors of the small intestine Unlike the large bowel the small intestine is rarely the seat of tumors. 5% all GIT tumours 5% all GIT tumours 1-2 % malignant GIT tumours Age >50 yr. GIT Neoplasms

There are several theories to explain this fact; 1. Rapid transit time decrease the time for contact of carcinogens with the mucosa. 2. The local immune system of the small bowel mucosa. 3. The alkaline pH of the succus entericus.

4. The absence of bacteria that might convert certain ingested products to carcinogens. 5. The presence of mucosal enzymes that destroy certain carcinogens.

The symptoms that associated with small bowel neoplasms are often vague & they include; 1. Epigasteric discomfort. 2. Nausea. 3. Vomiting. 4. Abdominal pain, which is often intermittent & colicky. 5. Diarrhea & bleeding.

Diagnosis by : barium follow through study, CT scan, endoscopy, capsule, endoscopy, 20-25% preoperative diagnosis In most of cases diagnosis occur at explorative laparotomy The most common indication for operation in patients with neoplasms of small bowel are obstruction, bleeding & pain.

Benign tumors The most common lesions are adenomas, liomyomas & lipomas, other benign tumors include hamartoma, fibromas, angiomas, lymphangiomas, Neurofibromas & hemangiomas.

A. Benign tumours more in distal part of small bowel: more in distal part of small bowel: 1. Leiomyomas & GIST tumours originated from interstial cells of Cajal originated from interstial cells of Cajal ( mesodermal in origin ) ( mesodermal in origin ) compose 0f 70 % spindle cell & compose 0f 70 % spindle cell & 30 % epithelial cells 30 % epithelial cells The benign form of these tumours are 3-4 times more common than malignant one They express CD 117 in 90 % of cases & CD 34 in 80 % of cases Treatment: local resection.

2. adenomas: 3 types:- True adenomas Villous adenomas Brunner adenomas Treated by primary resection if they are causing symptoms except for large villous adenomas which requires segmental resection. 3. lipomas: treated by simple excision

4. Peutz Jegar ( hamartomas ) This is an inherited syndrome & the mode of inheritance is by simple mendalian dominant. seen more frequently in the jejunum & ileum but the may affect whole the GIT & also extra GIT organs like the ovary, lungs, breasts & uterus. It consists of; Familial intestinal hamartomatous polyposis where it cause hemorrhage & often intussusception. Familial intestinal hamartomatous polyposis where it cause hemorrhage & often intussusception. Melnosis of the oral mucous membrane & the lips. Melnosis of the oral mucous membrane & the lips.

Histology; the polyps can be likened to trees & consist of smooth muscle fibers & covered by normal mucosa. the polyps can be likened to trees & consist of smooth muscle fibers & covered by normal mucosa. Treatment ; by segmental resection of severely involved segment only. by segmental resection of severely involved segment only. 5. haemangiomas : they are multiple in 60% of cases but most common site is the jejunum. In cases of bleeding the treatment is by segmental resection.

B. malignant small bowel tumours: 1. adenocarcinoma 50% 2. carcinoid tuomur 3. malignant GIST 20% 4. lymphomas 7-25%

Adenocarcinoma more in duodenum & jejunum, more in duodenum & jejunum, and it usually late in diagnosis. and it usually late in diagnosis. Occurring in carcinoma age group, prognosis depends on the stage of disease. prognosis depends on the stage of disease. Malignant GIST more in jejunum & ileum more in jejunum & ileum spread by direct invasion & by hematogenous way spread by direct invasion & by hematogenous way to liver,lungs & bone. to liver,lungs & bone. Prognosis depends on stage & grade of disease.

Lymphomas more in ileum, occurring at younger age group & seen more in patients with celiac disease & AIDS. Treatment of adenocarcinoma & lymphoma by: 1. wide local excision if not possible. 2. palliative resection if not possible 3. bypass operations

Treatment of malignant GIST tumours by Segment a resection with wide margin & if possible resection of liver metastasis. Chemotherapy & radiotherapy are of little role in adenocarcinoma but are helpful in lymphoma cases and Imatinib is useful in malignant GIST. Prognosis : > 50% had metastasis at laparotomy, 5 yrs survival is < 25%.

3- carcinoid tumor; (25%) These tumors occur throughout the GIT These tumors occur throughout the GIT & also in the bronchus, testis & ovary. & also in the bronchus, testis & ovary. The appendix is the commonest site involved (65%) followed by the ileum (25%). followed by the ileum (25%). These tumors arise in the cells of kulchitsky at the base of the crypts of lieberkuhn, at the base of the crypts of lieberkuhn, when metastasis occurs to the liver the disease is called when metastasis occurs to the liver the disease is called carcinoid syndrome. carcinoid syndrome.

The tumor produces 5HT (serotonin) which might be present as 5- hydroxt indol acetic acid in the urine during the attacks. Also it may produce kinins, PGs, kallikrin, substance P, neurotrophin, chromogranin A>90%, Hstamin & Dopamin. The clinical syndrome consists of reddish-blue cyanosis, flushing attacks, diarrhea, borborygmi, asthmatic attacks & eventually some times pulmonary & tricuspid valves stenosis. Classically the flushing attacks are induced by alcohol. Diagnosis by : estimation of 5HIAA in 24 hrs urine chromogranin A provocative test ( clinical test ) by giving patient pentagasterin calcium, epinephrine.

Treatment; Tumor < 1 cm local resection When small lesions discovered at appendectomy, removal of the appendix is the sufficient treatment. Tumors > 1cm & bigger + LNs involvement wide resection Eg : terminal ileum ---- Rt hemicolectomy Liver secondaries are Treated accordingly : Segmentectomy or lobectomy s.t liver transplantation ?? + medical treatment by somatostatin ( Octeriotide ) + antihistamins & alpha methyldopa & steroids. might help to reduce the severity of the attacks.

Prognosis : most better than other small intestinal malignancies most better than other small intestinal malignancies Small tumors has 100% 5 years survival rate Small tumors has 100% 5 years survival rate Regional disease 65% 5years survival rate Regional disease 65% 5years survival rate Distant metastasis 25 – 35 % 5 years survival rate Distant metastasis 25 – 35 % 5 years survival rate

Metastatic neoplasm : is the most common small bowel tumor reaching them from is the most common small bowel tumor reaching them from direct extension or direct extension or by implantation or by implantation or from extra-abdominal tumors; from extra-abdominal tumors; lungs, breast, lungs, breast, & more common from melanoma. & more common from melanoma.Treatment: local resection or bypass to relieve obstruction. local resection or bypass to relieve obstruction.