الفهرس 
Angiodysplasia of the ColonOnly 14 pages are availabe for public view
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Abstract
Angiomatous malformation of the gastro-intestinal tract is a type of birthmark or congenital growth made up of arteries, veins, capillaries or lymphatic vessels and they do not involute spontaneously. The pathogenesis of these tumors is not well defined. There are several different types of malformations and they are named according to which type of blood vessel is predominantly affected (Lucile Packard Foundation for Children’s Health, 2007).
There are several syndromes and diseases including these malformations such as angiodysplasia which is the most common vascular abnormality of the gastro-intestinal tract. After diverticulosis, it is the second leading cause of lower gastro-intestinal bleeding in patients older than 60 years. Diffuse cavernous hemangioma of the rectum and rectosigmoid colon is one of the rarest tumors found in colon. Blue rubber bleb nevus syndrome is a syndrome of multiple blue rubber bleb nevi associated with hemangiomas of the gastro-intestinal tract. Klippel-trenaunay-weber syndrome is a combination of cutaneous angiomatosis, varicose veins and enlargement of soft tissue which is ‘angiomatoid malformation’. Dieulafoy’s disease is a vascular anomaly characterized by the presence of a tortuous dysplastic artery in the submucosa. Osler-Weber-Rendu syndrome which is associated with the presence of multiorgan arteriovenous malformations. Pseudoxanthoma Elasticum is a genetic disorder characterized by progressive calcification and fragmentation of elastic fibers in the skin, the retina and the cardiovascular system. Caliber-Persistent Artery which is a retained caliber labial artery. Arteriovenous malformation (AVM) of the head of Pancreas which is a rare condition that may cause upper gastro- intestinal bleeding (Arguedas, et al., 2001). . Presentations of vascular malformations are hematemesis, melena or hematochezia. Iron deficiency anemia due to occult blood in stools. Other lesions as cutaneous lesions in Blue rubber bleb nevus syndrome (Richter, et al., 1984).
Diagnosis of vascular malformations depend on Laboratory Studies: as Compelet blood count, Serum iron level and Stool for occult blood. Imaging Studies: as selective mesenteric angiography. Radionuclide scanning using technetium Tc 99m–labeled red blood cells or 99mTc sulfur colloid. Angiography of resected specimens. Helical CT angiography. Barium enema and ultrasonography. Computed tomography and magnetic resonance imaging may be used to exclude other causes of rectal bleeding. Procedures:as endoscopy, visual inspection of the serosal side of the bowel during laparotomy, Intraoperative enteroscopy and angiographic catheter can be placed before surgery into the appropriate feeding vessel supplying the lesion, the surgeon then can identify the catheter during surgery and explore and resect the appropriate small bowel segment and finally diagnosis of vascular malformations by Histologic Findings (Alavi and Ring, 1981).
Treatment for vascular malformations depends upon the type of the malformation. Each type of malformation is treated differently. Laser therapy is usually effective for capillary malformations. Arterial malformations are often treated by embolization (blood flow into malformation is blocked by injecting material near the lesion). Venous malformations are usually treated by direct injection of a sclerosing (clotting) medication which causes clotting of the channels. Most often, a combination of these various treatments is used for effective management of the lesion (Lucile Packard Foundation for Children’s Health, 2007).
The results of ligation and embolization of the mesenteric vessels are not successful, although abdominoperineal resection was the most often recommended procedure. In recent years, sphincter-saving procedures have become popular if hemorrhage can be controlled and there is no evidence of malignant change. Low anterior resection with a minimal rectal cuff left in place, rectal mucosectomy and colo-anal pull-through are the most favorable sphincter-saving procedures (Öner and Altaca, 1993).
Gastric and duodenal lesions have been managed most commonly with endoscopic obliteration techniques. These techniques include monopolar electrocautery, heater probe, sclerotherapy, band ligation, and argon and neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers. Finally surgical resection is the definitive treatment (Krevsky, 1997).