A large polypoid arteriovenous malformation of the colon treated with a detachable snare: case report and review of literature

Case Reports

causing biliary obstruction, IDUS can be of value as an adjunct to ERCP. IDUS allows an examination of the wall layers of the biliary system and increases the ability of ERCP and other techniques to distinguish malignant from benign strictures of the biliary tree.7-9 In a prospective study by Domagk et al.7 of 60 patients with bile-duct strictures of undetermined etiology IDUS was performed in addition to ERCP in all cases. This strategy led to the correct preoperative diagnosis in 83% of the cases. A combination of ERCP and IDUS with transpapillary biopsy of the stricture established the correct preoperative diagnosis in 98% of the cases. The criteria we used to evaluate the IDUS images are identical to those used in the aforementioned publications.7-9,11 Criteria that suggest malignancy include a hypoechoic mass, heterogeneity of the internal echo pattern, irregularity of the outer border, and disruption of the normal sonographic structure of the CBD. In this rare case, heterotopic gastric tissue in the CBD caused a biliary obstruction that mimicked a malignancy on both ERCP and IDUS images. Nevertheless, in the majority of cases, IDUS is a valuable adjunct in distinguishing malignant from benign biliary-duct strictures.

5. Madrid C, Berrocal T, Gorospe L, Prieto C, Gamez M. Heterotopic gastric mucosa involving the gallbladder and biliary tree. Pediatr Radiol 2003;33:129-32. 6. Xeropotamos N, Skopelitou AS, Batsis C, Kappas AM. Heterotopic gastric mucosa together with intestinal metaplasia and moderate dysplasia in the gall bladder: report of two clinically unusual cases with literature review. Gut 2001;48:719-23. 7. Domagk D, Poremba C, Dietl KH, Senninger N, Heinecke A, Domschke W, et al. Endoscopic transpapillary biopsies and intraductal ultrasonography in the diagnostics of bile duct strictures: a prospective study. Gut 2002;51:240-4. 8. Farrell RJ, Agarwal B, Brandwein SL, Underhill J, Chuttani R, Pleskow DK. Intraductal US is a useful adjunct to ERCP for distinguishing malignant from benign biliary strictures. Gastrointest Endosc 2002;56: 681-7. 9. Vazquez-Sequeiros E, Baron TH, Clain JE, Gostout CJ, Norton ID, Petersen BT, et al. Evaluation of indeterminate bile duct strictures by intraductal US. Gastrointest Endosc 2002;56:372-9. 10. Inoue Y, Shibata T, Niinobu T, Ishida T, Sato T, Hanada M. Heterotopic gastric mucosa in the gallbladder: sonographic and CT findings. Abdom Imaging 2000;25:198-200. 11. Levy MJ, Vazquez-Sequeiros E, Wiersema MJ. Evaluation of the pancreaticobiliary ductal systems by intraductal US. Gastrointest Endosc 2002;55:397-408.

Current affiliations: Department of Gastroenterology, Department of Pathology, University Medical Center, Utrecht, The Netherlands. Presented at the Dutch Gastroenterology Society Congress: ‘‘NVGE voorjaarsvergadering,’’ March 21, 2003, Veldhoven, The Netherlands.

REFERENCES 1. Blundell CR, Kanun CS, Earnest DL. Biliary obstruction by heterotopic gastric mucosa at the ampulla of Vater. Am J Gastroenterol 1982;77: 111-4. 2. Evans MM, Nagorney DM, Pernicone PJ, Perrault J. Heterotopic gastricmucosa in the common bile-duct. Surgery 1990;108:96-100. 3. Hamazaki K, Fujiwara T. Heterotopic gastric mucosa in the gallbladder. J Gastroenterol 2000;35:376-81. 4. Kalman PG, Stone RM, Phillips MJ. Heterotopic gastric tissue of the bile duct. Surgery 1981;89:384-6.

Presented at the Dutch Internal Medicine Congress: ‘‘de internistendagen,’’ May 16, 2003, Maastricht, The Netherlands. Reprint requests: Rutger Quispel, MD, Department of Gastroenterology, University Medical Center, PO Box 85500, 3508 GA Utrecht, The Netherlands. Copyright ª 2005 by the American Society for Gastrointestinal Endoscopy 0016-5107/$30.00 PII: S0016-5107(05)00369-X

A large polypoid arteriovenous malformation of the colon treated with a detachable snare: case report and review of literature Jeong-Seon Ji, MD, Kyu-Yong Choi, MD, Bo-In Lee, MD, Byung-Wook Kim, MD, Hwang Choi, MD, Se-Hyun Cho, MD, Woo-Chul Chung, MD, In-Seok Lee, MD, Kang-Moon Lee, MD, Hiun-Suk Chae, MD, In-Sik Chung, MD, Kyoung-Mee Kim, MD Seoul, Korea

Arteriovenous malformation (AVM) is a common cause of lower-GI bleeding in elderly patients, but it is relatively rare in people under 50 years old.1 Generally, it appears as a flat or elevated, bright red lesion on endoscopy2; a polypoid shape is extremely rare in patients with colonic AVM.

Recently, we encountered a case of a large polypoid AVM of the colon in an 81-year-old patient. We managed the active bleeding and obtained enough tissue to diagnose AVM by applying a detachable snare before the biopsy. Eventually it proved possible to remove the remaining mass

172 GASTROINTESTINAL ENDOSCOPY Volume 62, No. 1 : 2005

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Case Reports

Figure 2. Follow-up colonoscopy.

Figure 1. A, Initial colonoscopy. B, After application of the detachable snare.

completely and safely by elective EMR without risking emergency laparotomy.

CASE REPORT An 81-year-old man presented with hematochezia for 4 days. He had been taking antihypertensive medication for 3 years. Family history was unremarkable. Blood pressure was 130/90 mm Hg, and pulse rate was 110 beats/min. Hb was 8.1 g/dL (normal: 13-17 g/dL), and hematocrit was 24% (37%-47%). EGD disclosed no abnormality. Colonoscopy revealed a 3.5  2.2-cm semipedunculated polypoid mass in the proximal transverse colon (Fig. 1A). Because the mass had normal-looking epithelium with multiple hemorrhagic spots, it needed to be differentiated from a hypervascular submucosal tumor, e.g., polypoid AVM. For hemostasis and to prevent bleeding from the biopsy, a detachable snare (HX-20U; Olympus Optical Co, Ltd, Tokyo, Japan) was

applied to the base of the mass and a biopsy was performed (Fig. 1B). Hematochezia stopped shortly after colonoscopy. Histopathologic findings were consistent with AVM.

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Volume 62, No. 1 : 2005 GASTROINTESTINAL ENDOSCOPY 173

Figure 3. A, The histology of the remaining mass (H&E, orig. mag. 40), showing dilated blood vessels (arrowheads). B, Internal laminae within the vessel walls (arrowheads) (Verhoeff ’s elastic stain, orig. mag. 400).

Case Reports

TABLE 1. Summary of reported polypoid arteriovenous malformations

2

Koziara et al

Park et al4 5

Age (y)/ gender

Chief complaint

84/F

Hematochezia

58/M

Location

Maximal diameter (cm)

Sigmoid colon

Gross finding

Treatment

Result

3.5

Pedunculated

Snare polypectomy Hemostasis

Iron deficiency Transverse colon anemia

1.5

Pedunculated

Snare polypectomy Improvement of anemia

41/M

Hematochezia

Descending colon

1.0

Pedunculated

Snare polypectomy Hemostasis

53/M

Hematochezia

Sigmoid colon

2.0

Pedunculated

Snare polypectomy Hemostasis

6

Maeng et al

59/F

Hematochezia

Transverse colon

6.0

Pedunculated

Surgery

Present case

81/M

Hematochezia

Transverse colon

3.5

Semipedunculated Application of a detachable snare and EMR

D’Arienzo et al

Three days later, we performed follow-up colonoscopy. Although the detachable snare and most of the mass had gone (Fig. 2), there was no sign of hemorrhage. We removed the residual mass by conventional EMR and applied two hemoclips (HX-6UR; Olympus) to prevent bleeding. Microscopic examination showed ulceration, hemorrhage, and dilated blood vessels with thick walls in the mucosa and the submucosa. Verhoeff ’s elastic stain revealed internal laminae within the vessel walls, which suggested that the AVM consisted mainly of veins (Fig. 3A and B). In 5 months of follow-up, there has been no recurrence of bleeding.

DISCUSSION Colonic AVM also is known as angiodysplasia or vascular ectasia. These terms are suggestive of degenerative lesions. Colonic AVM is thought to result from intermittent low-grade obstruction of submucosal veins, because they penetrate the muscular layers of the colon and cause small arteriovenous communications.3 Polypoid AVMs are extremely rare in the large intestine and only 5 cases have been reported in the English language literature (Table 1).2,4-6 All the patient were over 40 years old, with no gender preference. The most common initial symptom was hematochezia, and there was no difference in frequency between the right and the left colon. Maximal diameter was between 1.0 and 6.0 cm. All reported cases apart from ours were pedunculate in form. Most of the cases were mistaken for a polyp and, as a result, diagnosis was made by snare polypectomy. Because we had previously experienced a case of polypoid AVM,6 we suspected the mass to be a hypervascular tumor, e.g., polypoid AVM, on the basis of the gross findings alone. We, therefore, applied a detachable snare to stop hemorrhaging and to prevent bleeding from the biopsy, and then we were able to obtain enough tissue for pathologic diagnosis. If we had performed snare polypectomy on the 174 GASTROINTESTINAL ENDOSCOPY Volume 62, No. 1 : 2005

Hemostasis Hemostasis

initial colonoscopy, as in the other cases, there could have been massive hemorrhage because of its hypervascularity, submucosal involvement, and subpedunculation. Detachable snares placed around the stalk of the polyp generally detach within 1 week. Although the snare detached sooner than we expected in this case, there was no hemorrhage. It seemed that the bleeding had already stopped because of blockage of blood flow and compressive hemostasis by the snare.7 As a result, we were able to avoid the risk of massive hemorrhage, an emergency operation, and general anesthesia, induced by biopsy or snare polypectomy in an elderly patient. At the time of follow-up colonoscopy, we thought that the risk of bleeding was low considering the small size of remnant. Therefore, we performed EMR. When practicing EMR, we could apply a snare on adjacent normal tissue without involving AVM, so that we reduced the risk of bleeding. In summary, when a colonic polypoid AVM is small and pedunculated, the lesion can be removed safely by snare polypectomy. However, with large or subpedunculated forms, biopsy or snare polypectomy may lead to unremitting bleeding and may even require an operation.6 Our experience suggests that it may be useful to attach a detachable snare to the base of a colonic polypoid AVM to achieve hemostasis and to prevent hemorrhage from the biopsy.

REFERENCES 1. Vernava AM 3rd, Moore BA, Longo WE, Johnson FE. Lower gastrointestinal bleeding. Dis Colon Rectum 1997;40:846-58. 2. Koziara FJ, Brodmerkel GJ, Boylan JJ, Ciambotti GF, Agrawal RM. Bleeding from polypoid colonic arteriovenous malformations. Am J Gastroenterol 1996;91:584-6. 3. Boley SJ, Sammarton R, Adams A, DiBiase A, Kleinhaus S, Sprayregen S. On the nature and etiology of vascular ectasias of the colon: degenerative lesion of aging. Gastroenterology 1997;72:650-60.

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Case Reports 4. Park ER, Yang SK, Jung SA, Shim KN, Jung HY, Kim HR, et al. A case of pedunculated arteriovenous malformation presenting with massive hematochezia. Gastrointest Endosc 2000;51:96-7. 5. D’Arienzo A, Manguso F, D’Armiento FP, Bennato R, Somma P, Pisani A, et al. Colonoscopic removal of a polypoid arteriovenous malformation. Dig Liver Dis 2001;33:435-7. 6. Maeng LS, Choi KY, Lee AH, Kang CS, Kim KM. Polypoid arteriovenous malformation of colon mimicking inflammatory fibroid polyp. J Gastroenterol 2004;39:575-8. 7. Matsushita M, Hajiro K, Takakuwa H, Kusumi F, Maruo T, Ohana M, et al. Ineffective use of a detachable snare for colonoscopic polypectomy of large polyps. Gastrointest Endosc 1998;47:496-9.

Current affiliations: Departments of Internal Medicine and Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea. Reprint requests: Kyu-Yong Choi, MD, Division of Gastroenterology, Department of Internal Medicine, Our Lady of Mercy Hospital, The Catholic University of Korea, #665, Bupyong 6-dong, Bupyong-gu, Incheon, 403-720, Republic of Korea. Copyright ª 2005 by the American Society for Gastrointestinal Endoscopy 0016-5107/$30.00 PII: S0016-5107(05)00329-9

Colonoscopic features of simvastatin-induced colitis suggest ischemia as an etiologic mechanism Felix W. Leung, MD, Jack Lieberman, MD, Neil Fagen, MD, Dennis Kasimian, MD, Raj Wick, MD Los Angeles, California, USA

We report on a patient with drug-induced colitis for over 2 years not initially recognized to be caused by simvastatin. The patient did not improve with mesalamine, prednisone, and 6-mercaptopurine (6-MP). Complications included prednisone-induced hyperglycemia, 6-MP-induced febrile illness, and acute gout attack. Withdrawal of 6-MP and simvastatin led to resolution of all symptoms. In retrospect, colonoscopic documentation revealed features characteristic of an ischemic etiology (segmental and patchy mucosal abnormalities, and discrete ulcerations with irregular margins). Colonic mucosal biopsy specimens showed histologic evidence consistent with ischemia. The diagnosis also was supported by the reversible clinical course. In patients with chronic diarrhea, should colonoscopists encounter these characteristic findings, consideration should be given to the diagnosis of drug-induced ischemic colitis. Recognition of these associations also may obviate unnecessary diagnostic assessments in patients with simvastatin-induced colitis and may avoid ineffective therapy and additional treatment-related complications. Although drug-induced ischemic colitis is well described, endoscopic recognition has not been emphasized. Drugs associated with ischemic colitis include the following: alosetron; amphetamines, such as metamphetamine and dextroamphetamine; chemotherapeutic agents; cocaine, cyclosporine; danazol; digitalis; ergot; gold; imipramine; interferon; ibuprofen; meloxicam; mycophenolate; other nonsteroidal anti-inflammatory drugs; oral contraceptives; Premarin (Wyeth-Ayerst, Madison, NJ); pseudoephedrine; psychotropic drugs; sumatriptan; vasopressin; and voglibose (unpublished review data).1 While diarrhea is a known side effect of simvastatin,2 only two cases of colitis3,4 have been linked directly to its use, and neither were considered

explicitly caused by colonic ischemia. Nonetheless, one patient with ischemic colitis thought to be caused by alosetron also was taking simvastatin.5 We report here about a patient with colitis, who, in retrospect, had features characteristic of an ischemic etiology. The colitis resolved after simvastatin was discontinued. We discuss the endoscopic features for prompt recognition.

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Volume 62, No. 1 : 2005 GASTROINTESTINAL ENDOSCOPY 175

CASE REPORT A 76-year-old man, a retired physician, was evaluated for diarrhea of 2 years’ duration. He had 5 to 6 loose bowel movements daily with mucus and associated urgency, and occasional episodes of fecal incontinence. His medications included 20 mg/d simvastatin, 81 mg/d aspirin, and multivitamins. More explosive diarrhea had occurred with 40 mg/d atorvastatin, which was replaced by simvastatin. The milder form of diarrhea under evaluation began 7 to 10 days after the start of simvastatin. Physical examination revealed large hemorrhoids, and stool was positive for occult blood. Stool studies were negative for bacterial pathogens, ova, parasites, or Clostridium difficile toxin. Colonoscopy revealed colitis extending from the rectum to the mid transverse colon. A 10-cm segment in the sigmoid colon (approximately 18-28 cm from the anal verge) was spared. The remainder of the transverse colon, hepatic flexure, and ascending colon also appeared normal. There were several spotty areas of inflammation involving the cecum and the ileocecal valve. Besides demonstrating segmental involvement of the ‘‘colitis,’’ the colonoscopic features initially were considered to be nonspecific (Fig. 1A and B). Transverse colon biopsy revealed mild focal active colitis, with denudation of surface epithelium. A descending