Inferior mesenteric arteriovenous fistula: Case report and world-literature review

Percutaneous transhepatic vascular embolization for a mesenteric arteriovenous malformation leading to decreased portal pressure in a patient with alcoholic liver cirrhosis: A case report

Arteriovenous malformations in the abdominal region are rare, and they are known to occasionally cause portal hypertension. A 66-year-old man with a chief complaint of fatigue and blood tests showing hepatic dysfunction was seen for a more detailed examination. Abdominal contrast-enhanced computed tomography showed an anastomosis of the ileal artery and ileal vein via a nidus within the mesentery. In addition to alcoholic cirrhosis from a history of high alcohol intake, the patient was diagnosed with portal hypertension from increased portal pressure due to an arteriovenous malformation in the mesentery. Vascular embolization with a percutaneous transhepatic approach was performed for the mesenteric arteriovenous malformation. The ileal vein, which was the dominant outflow vein, was embolized, and the blood flow in the arteriovenous malformation disappeared. A decrease in portal pressure of 29% was confirmed. There were no complications from the embolization. In cases of mesenteric arteriovenous malformations that contribute to portal hypertension, treatment of the malformations can be expected to decrease portal pressure. Compared with surgical intestinal resection, endovascular treatment that can be done with low invasiveness is thought to be a possible option.

A Rare Case of Hughes-Stovin Syndrome Presenting with Ischemic Colitis Caused by an Arteriovenous Malformation

Hughes-Stovin syndrome (HSS) is an exceedingly rare disease characterized by thrombotic phlebitis and pulmonary or bronchial artery aneurysms. A 68-year-old man presented with ischemic colitis, and angiography revealed occlusion of the inferior mesenteric vein and arteriovenous malformation in the inferior mesenteric artery region. Medical treatment was unsuccessful, and a left hemicolectomy was therefore performed following coil embolization. Subsequently, a pulmonary artery aneurysm was incidentally detected, and coil embolization was performed. However, the patient developed deep vein thrombosis and a pulmonary embolism, which led to a diagnosis of HSS. To our knowledge, this is the first report of ischemic colitis as a presenting feature of HSS.

Imaging of the Inferior Mesenteric Vasculature

The inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV) supply and drain blood from the distal colon and rectum, respectively. Routinely imaged at cross-sectional imaging of the abdomen and pelvis, these vessels play a vital role in gastrointestinal tract health but may be neglected due to their diminutive caliber relative to other mesenteric vessels and potential lack of inclusion in routine search patterns. The authors describe and illustrate normal and abnormal appearances of the IMA and IMV and findings that are diagnostic of primary vascular abnormalities or can offer diagnostic clues. After the embryologic features, normal anatomy, and anatomic variants of the IMA and IMV are reviewed, various manifestations of IMA and IMV abnormalities, such as aneurysm and pseudoaneurysm, stenosis, occlusion, dissection, hemorrhage, arteriovenous malformations and fistulas, tumoral invasion, vasculitis, and perivascular lymphatic dilatation, are explored with use of case examples. The role of the IMA and IMV as collateral vasculature, including the clinical scenarios of superior mesenteric arterial occlusion, aortic endoleak, and portosystemic venous shunt, are discussed. Finally, diagnostic clues that the inferior mesenteric vessels and adjacent soft tissues can provide, including mesenteric venous gas, compression or displacement from bowel volvulus or internal hernias, lymphadenopathy, and venous flow artifacts, are highlighted. The authors provide a comprehensive reference for radiologists who evaluate the IMA and IMV on cross-sectional images and shine a spotlight on these neglected but important vessels. ©RSNA, 2024 Supplemental material is available for this article.

Congestive colopathy in a patient with arteriovenous malformations and multiple mesenteric thromboses

Arteriovenous malformations (AVMs) in mesenteric vessels are exceptionally rare. These congenital vascular anomalies lead to direct vascular flow between the highly pressured arterial system and the low-pressure venous system. We describe the case of a patient with prior left colectomy for splenic flexure colonic adenocarcinoma presenting with persistent abdominal pain after developing multiple mesenteric thromboses. CT and colonoscopy showed left hemicolon congestion, anastomotic stenosis and mucosal oedema. Mesenteric angiogram revealed AVMs in the right colic and left colic arteries. Embolisation of the left colic AVM led to symptom resolution without recurrence at interval follow-up.

Giant Inferior Mesenteric Vein Aneurysm Secondary to Iatrogenic Inferior Mesenteric Arteriovenous Fistula

PURPOSE

Visceral venous aneurysms are rare, especially in the inferior mesenteric vein (IMV). We report a giant IMV aneurysm secondary to an iatrogenic arteriovenous fistula (AVF).

CASE REPORT

A woman presented with an incidental finding of a 7 cm large IMV aneurysm and an inferior mesenteric arteriovenous shunt. The patient underwent successful endovascular occlusion of the shunt to avoid aneurysm rupture and portal hypertension.

CONCLUSION

Embolization is a possible treatment strategy for mesenteric venous aneurysms with an AVF.

CLINICAL IMPACT

We describe an unusual mesenteric AV-shunt from a surgical crush injury that caused a giant venous mesenteric aneurysm and offer technical aspects on minimally invasive endovascular treatment.

Laparoscopic sigmoid colectomy for transverse colonic varices due to an inferior mesenteric arteriovenous fistula

BACKGROUND

Colonic varices are a rare gastrointestinal anomaly often associated with portal hypertension. Arteriovenous fistula (AVF) in the inferior mesenteric artery (IMA) region is even rarer. Diagnosis and treatment of these entities present unique challenges, especially when the IMA is involved.

CASE PRESENTATION

A 48-year-old man with a history of cholecystectomy presented with after a positive fecal occult blood test. Investigations revealed varices from the splenic flexure to the transverse colon and suspected AVF in the IMA region. Given the high risk and low efficacy of endoscopic and radiological interventions, laparoscopic sigmoidectomy was performed. This surgical approach successfully addressed both the AVF and the associated varices.

CONCLUSION

This case underscores the importance of surgical intervention for AVF and colonic varices in the IMA region, particularly when other treatment options pose high risks and have limited efficacy. The favorable postoperative outcome in this case highlights the effectiveness of carefully chosen surgical methods when managing such complex and rare conditions.

Hereditary hemorrhagic telangiectasia involving portal venous system: A case report and review of the literature

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder with an incidence of approximately 1 in 5000 in the general population. It is characterized by vasodilation, which affects specific organs, such as the skin, mucous membranes, brain, lungs, gastrointestinal tract, liver, and others. However, HHT rarely involves the portal venous system to cause serious clinical complications.

CASE SUMMARY

A 68-year-old woman was admitted to the emergency department due to four consecutive days of abdominal pain and bloody stool and was subsequently diagnosed with HHT. Computed tomography angiography confirmed the presence of an arteriovenous fistula (AVFs). Considering this specific manifestation, whole exome sequencing was performed. After a comprehensive evaluation, a selective superior mesenteric artery embolization was prioritized to avoid intestinal ischemia. The postoperative symptoms of the patient were quickly relieved. Unfortunately, two months post-procedure the patient died from intestinal necrosis and abdominal infection related to remaining AVFs.

CONCLUSION

For patients with diffuse superior mesenteric AVFs, selective mesenteric arterial embolization may lead to positive short-term outcomes.

A Case of Refractory Esophageal Varices Caused by an Inferior Mesenteric Arteriovenous Malformation with All Portal System Occlusion Successfully Treated via Transarterial Embolization

Inferior mesenteric arteriovenous fistulas/malformations are rare, reported in only 40 cases as of 2021. Their main manifestations include portal hypertension and ischemic bowel disease. We report the case of a 50-year-old man with refractory esophageal varices caused by this condition that was successfully treated with transarterial embolization. Computed tomography revealed an inferior mesenteric arteriovenous malformation and ascending blood flow into the esophageal varices through a remarkably dilated marginal vein. All portal systems were occluded, possibly because of the myointimal hyperplasia of the inferior mesenteric vein. The patient recovered without hemorrhagic events after transarterial embolization and endoscopic injection sclerotherapy. This is the first report of an inferior mesenteric arteriovenous malformation resulting in refractory esophageal varices with all-portal system occlusion successfully treated with transarterial embolization.

Inferior mesenteric artery arteriovenous malformation, a rare cause of ischemic colitis: A case report

RATIONALE

An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels that connects the arteries and the veins. Because normal capillary bed is partially or completely absented in the AVM, the blood passes quickly from the arteries to the veins, which disrupts normal blood flow and oxygen supply to the surrounding tissues. This is called "steal phenomenon," and in the inferior mesenteric artery (IMA) territory, this may lead to abdominal pain, gastrointestinal bleeding, portal hypertension, and even ischemic colitis.

PATIENT CONCERNS

A 67-year-old man presented to our emergency department because of left side abdominal pain.

DIAGNOSES

The abdominal computed tomography with contrast enhancement revealed a cluster of abnormal vascular lesions abutting the IMA with early opacification of the left colonic marginal vein. In addition, poor enhancement of segmental colonic wall was found from proximal descending colon to middle rectum. The diagnosis of AVM of the IMA and ischemic colitis was made.

INTERVENTIONS

The patient underwent left hemicolectomy as well as the AVM resection.

OUTCOMES

He was discharged uneventfully after the surgery without complications.

LESSONS

IMA AVM carries the risk of ischemic colitis. computed tomography scan is helpful not only to the diagnosis of AVMs but also to exclude other lesions as well. Treatment options include endovascular embolization, surgical intervention, and a combination of both. Due to the complexity of this disease, treatment requires a case-specific multidisciplinary approach and a coordination of medical, radiological, and surgical staffs.

Trans-arterial embolization of a Yakes type IIb inferior mesenteric arteriovenous malformation: A case report and literature review for angio-architecture analysis

We herein report a case of acute, massive lower gastrointestinal bleeding caused by Yakes type IIb inferior mesenteric arteriovenous malformation, which was successfully treated with endovascular embolization. The Yakes arteriovenous malformation classification provides curative treatment strategies based on specific angioarchitecture, thus serving as a valuable guide during treatment planning. We reviewed reported cases from 1988 to 2022 and conducted an angioarchitecture analysis based on the Yakes classification. We analyzed these reported cases to estimate the treatment success rates of surgery and embolization.

Invasive investigation in cases of visceral AVM may be fatal: A rare case report

Introduction and importance

Visceral arteriovenous malformations (AVMs) are extremely rare with only a few cases described in the literature. We have encountered a mesenteric AVM in a 23-year-old girl. Considering the rarity of this entity and diagnostic dilemma, we herein describe a case of mesenteric AVM along with the review of literature.

Case presentation

A 23-year-old female presented with pain and lump in lower abdomen. During her workup to conclude a final diagnosis, Fine needle aspiration cytology (FNAC) was done. Post FNAC patient went into shock and immediately emergency laparotomy was done. The bleeding mass was resected along with involved gut and anastomosis was done. Histopathology suggested AVM. She was doing well at 2 months of follow up.

Clinical discussion

AVM is the rare cause of ischaemic colitis. It can create a diagnostic dilemma with its unusual presentation and its rarity even for both radiologists and surgeons. Usually such malformation reported after trauma or any surgical intervention, but in our case there was no such history of trauma which makes this case more interesting. Invasive investigation is recommended in such condition but needs to be very cautious. As in this index case invasive procedure lead to severe bleeding. Although definitive treatment are embolization and surgery.

Conclusion

Invasive procedure should be avoided in case of AVM. If angiography is not available its mandatory to keep operating room ready before any invasive procedure.

•

Only few cases of visceral arteriovenous malformations are reported in the literature.

•

Invasive investigation should be avoided in case of AVM.

•

Because of more lymphatic component sometimes contrast enhancement is not obvious.

•

The early surgical intervention is wise decision even in case of diagnosis dilemma.

Endovascular approach in the management of idiopathic myointimal hyperplasia of the inferior mesenteric vein

Background

Idiopathic myointimal hyperplasia of the mesenteric vein (IMHMV) is a rare, often undiagnosed pathology affecting the colon. Patients typically present with severe abdominal pain and inflammation caused by smooth muscle proliferation of the veins, leading to arterialization, stenosis, and potential occlusion. The etiology remains unclear, but it has been hypothesized that an arteriovenous connection may be associated with the pathology. This is the first reported case indicating such an association. This case additionally highlights the potential utility of endovascular treatment, as endovascular embolization is generally a less invasive alternative to surgical resection in the treatment of such vascular disorders.

Case Presentation

This report describes a 24-year-old female patient with findings of colitis and an abnormal arteriovenous connection of the inferior mesenteric arterial and venous systems. Partial embolization of this arteriovenous connection temporarily improved the patient’s condition, but her symptoms ultimately returned due to the presence of multiple smaller feeder vessels not amenable to embolization, necessitating colonic resection for definitive treatment. Although prior reports have hypothesized that arterial pressurization of the veins may precipitate myointimal hyperplasia, to the authors’ knowledge, this is the first report of IMHMV with an associated abnormal arteriovenous connection.

Conclusions

This case illustrates the possibility of an association between an arteriovenous connection and IMHMV. This rare diagnosis should be considered in patients with a similar presentation of abdominal pain after common etiologies like IBD have been excluded.

Detection and Intervention of Clinically Masquerading Inferior Mesenteric Artery AVMs

We demonstrate a rare case of inferior mesenteric artery arteriovenous malformations leading to ischemic colitis in a 76-year-old female. Our patient presented with three months of nausea, vomiting, and diarrhea. Colonoscopy displayed diffuse mucosal vascular congestion while CTA and MRA displayed AVMs in the region of the IMA; however, cohesive clinical agreement on AVM from multiple specialties was difficult given its rare occurrence and nonspecific clinical, histopathologic, and directly visualized findings. The three noted dominant AVMs were eventually selected with coil and liquid embolization with successful cessation of symptoms and no major complications. Our discussion focuses on intervention and stressing the importance of radiologic findings, as IMA AVMs, rarely present as ischemic colitis and therefore can clinically masquerade as other etiologies.

Arteriovenous Fistula of Superior Mesenteric Artery: An Unusual Cause of an Massive Lower Gastrointestinal Bleeding

Introduction

The most common causes of lower gastrointestinal (GI) hemorrhage are diverticulosis and angiodysplasia. Arteriovenous fistula (AVF) of the intestine is an uncommon cause of GI hemorrhage.

Case Presentation

Herein, we report a case of an embolization of an AVF originated from the superior mesenteric artery and vein as a cause of acute massive lower GI bleeding.

Conclusion

The patient underwent a right hemicolectomy and ileotransversostomy.

Inferior mesenteric arteriovenous fistula with colonic ischemia: a case report and review of the literature

Inferior mesenteric arteriovenous fistula is a rare abnormal high flow communication with only 40 primary and secondary cases reported in literature. Shunting of arterial flow through the inferior mesenteric vein to the portal system can cause a variety of nonspecific clinical signs and symptoms usually associated with the diagnosis of arteriovenous malformation. Symptom intensities are flow-dependent and can range from minimal abdominal symptoms to severe heart failure due to left to right shunt. We report the case of a 72-year-old man without past history of abdominal surgery or trauma who was referred to our department for a 2-month history of intermittent diarrhea and abdominal pain caused by an arteriovenous fistula involving the left colic artery and the inferior mesenteric vein. A progressive and spontaneous improvement of symptoms and a control CT scan that confirmed the reduction of venous vascular engorgement and regression of parietal thickening of the left and sigmoid colon permitted a non-operative management.Inferior mesenteric arteriovenous fistula can be a rare cause of ischemic colitis and, if necessary, an appropriate treatment based on high clinical suspicion can reduce the risk of complications related to a missed diagnosis.

Natural history of inferior mesenteric arteriovenous malformation that led to ischemic colitis: A case report

BACKGROUND

Ischemic colitis with inferior mesenteric arteriovenous malformation (AVM) is a rare disease. Although a few reports have been published, no report has described the natural history of idiopathic mesenteric AVM.

CASE SUMMARY

A 50-year-old male was admitted to our hospital due to abdominal pain that had persisted for 3 mo and bloody diarrhea. He had no history of trauma or abdominal surgery. He had undergone two colonoscopies 6 mo and 2 years ago, and they showed only a polyp. He was diagnosed with ischemic colitis with inferior mesenteric AVM following contrast-enhanced abdominal computed tomography (CT) and underwent rectal low anterior resection. He has not had a recurrence of symptoms for 3 years. His history showed that he had undergone non-enhanced abdominal CT 2, 5, and 8 years ago when he had attacks of urinary stones. Retrospectively, dilation of blood vessels around the rectosigmoid colon could have been detected 5 years ago, and these findings gradually became more evident.

CONCLUSION

This is the first report of the natural history of inferior mesenteric AVM.

Inferior mesenteric arteriovenous fistula during treatment with bevacizumab in colorectal cancer patient: A case report

BACKGROUND

Fistula formation is a severe adverse event related to antiangiogenetic agents such as bevacizumab and inferior mesenteric arteriovenous fistula (IMAVF) is a result of acquired factor, especially colon surgery. However, IMAVF occurs very rarely and there are few reports in patients during chemotherapy. We report a case of a patient who developed IMAVF during treatment with bevacizumab in metastatic colorectal cancer (mCRC) after colon surgery.

CASE SUMMARY

An 81-year-old man was diagnosed with descending colon cancer and underwent left hemicolectomy without any complications. He was definitely diagnosed with high-risk stage 2 and received tegafur-uracil plus leucovorin as adjuvant chemotherapy. Three years and 6 mo after the operation, the cancer relapsed with peritoneal dissemination. The patient underwent CyberKnife radiosurgery targeting the recurrent tumor and received chemotherapy with S-1 plus bevacizumab. At 1 year after chemotherapy, he complained of severe diarrhea, which is suspected drug-induced colitis. As diarrhea worsened despite the termination of treatment, he underwent colonoscopy and computed tomography (CT) scans that revealed edematous change from sigmoid to rectosigmoid colon. CT scans also revealed an aneurysm adjacent to the inferior mesenteric vein and multidetector CT angiography showed the IMAVF. Elective angiography confirmed the diagnosis of an IMAVF and it was successfully treated by arterial embolization. The patient resumed chemotherapy with only S-1 6 mo after embolization.

CONCLUSION

Clinicians should keep in mind the probability of severe diarrhea arose from IMAVF in mCRC patients treated with bevacizumab.

A rare case of acute congestive ischaemic colitis related to combined superior and inferior mesenteric arteriovenous malformations

Visceral arteriovenous malformations (AVMs) are extremely rare with only a few cases described within the literature. To date, no cases of ischaemic colitis related to arteriovenous malformations affecting both superior and inferior mesenteric arteries have been reported. We report the first case of acute ischaemic colitis caused by venous congestion and reduced arterial flow due to combined AVMs in the territory of superior and inferior mesenteric arteries in a 51-year-old patient. After a multidisciplinary meeting, interventional radiology embolization was considered to be of unlikely benefit due to extensive varicosities; therefore, surgical treatment in the form of open subtotal colectomy and end ileostomy was performed. This case report demonstrates the severity and the complexity in the management of AVM-related ischaemic colitis, together with a review of the literature.

Curative embolization of iatrogenic inferior mesenteric arteriovenous fistula 14 years after right hemicolectomy

Inferior mesenteric arteriovenous fistula (IMAVF) is a rare condition with 40 reported cases. It can be of congenital, idiopathic or acquired etiology. Acquired IMAVF occurs after trauma or has an iatrogenic origin due to abdominal interventions, mainly operations involving the left hemi-colon. A new case of iatrogenic IMAVF is described, which became symptomatic 13 years after right hemicolectomy and was diagnosed radiologically one year later. This case was treated successfully by means of endovascular arterial embolization. To our knowledge, this is only the second reported case of acquired IMAVF following right hemicolectomy.

A rare case of simultaneous rectal and gastric carcinomas accompanied with inferior mesenteric arterioportal fistula: case report

BACKGROUND

Inferior mesenteric arterioportal fistula (APF) is rare as only 35 case reports in the literature. We herein presented a case of simultaneously double cancer in the rectum and stomach with inferior mesenteric APF, which is the first case report by searching using PubMed. Combination of interventional embolization and surgical operation seemed to be optimal treatment for avoiding postoperative complications and the curability.

CASE PRESENTATION

A 66-year-old male with epigastric pain was admitted to a practitioner. He underwent a gastroscopy with biopsy, and cancer located in the lesser curvature of the gastric cardia was found. Enhanced CT did not reveal wall thickening of the stomach and distant metastases, but several swollen lymph nodes were observed in the right cardia. In the arterial phase, dilation of inferior mesenteric vein (IMV) and superior rectal artery (SRA) were noted, which raised suspicions of an arterioportal communication. Colonoscopy revealed a type 2 rectal tumor located 12 cm from the anal verge. The histological diagnosis of well-differentiated tubular adenocarcinoma was confirmed by biopsy. At a first step, we planned to perform a radiological embolization of inflow vessels to APFs except for SRA. Additionally, we determined the interval time of 1 month between the first low anterior rectal resection and the sequential gastrectomy for the purpose of decreasing portal pressure. The postoperative course was uneventful without hemorrhagic complications, and S-1 was taken internally 1 year as adjuvant chemotherapy for gastric cancer. The patient still lives without recurrence of this cancer with APF and portal vein thrombosis 2.5 years after the aforementioned surgeries.

CONCLUSION

Inferior mesenteric APF and/or arteriovenous fistula (AVF) would be consisted of the several inflow arteries as superior rectal, internal iliac, and median sacral arteries, and outflow veins as inferior mesenteric, internal iliac, and median sacral veins. To determine the therapeutic strategy for left-sided colorectal cancers with abnormal vessel communications of the pelvis, it is significant to comprehend distribution and component vessels of APF and/or AVF.

Spontaneous inferior mesenteric arteriovenous fistula as a cause of severe portal hypertension and cardiomyopathy

Inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV) fistulas or malformations are extremely rare, with only 36 cases reported. Low incidence and nonspecific clinical signs and symptoms make mesenteric arteriovenous fistulas difficult to diagnose. We describe a case of a primary IMA-IMV fistula. Our patient presented with severe portal hypertension and cardiomyopathy along with robust arteriovenous connections between the IMA and IMV. Arterial embolization in this patient had to be followed by venous embolization for successful resolution of portal hypertension and cardiomyopathy. This case also highlights that close outpatient monitoring for treatment failure and recurrence is necessary for this disease process.

Inferior mesenteric arteriovenous fistula with nonpulsatile abdominal mass: A case report and a mini-review

RATIONALE

Inferior mesenteric arteriovenous fistula (IMAVF) is a rare condition principally characterized by portal hypertension and ischemic bowel disease. Up to now, only 30 cases have been reported. Presented here is an IMAVF patient with nonpulsatile abdominal mass as the main manifestation.

PATIENT CONCERNS

A 62-year-old Chinese male who complained of abdominal discomfort for a month was admitted to our hospital. Physical examination revealed a hard and hardly mobile mass.

DIAGNOSES

Space-occupying lesions were first suspected but endoscopy did not reveal any masses. The computed tomography angiography exhibited no definite boundary between the inferior mesenteric artery and vein. The patient was diagnosed with IMAVF.

INTERVENTIONS

The treatment of IMAVF mainly includes intra-arterial embolization and surgery. In our case, fistulas were complex and the patient had symptoms of colon ischemia, so we suggested a surgical resection instead of embolization. And the postoperative biopsy also confirmed the diagnosis.

OUTCOMES

After surgery, gastrointestinal symptoms disappeared and the patient began to gain weight gradually. During the follow-up, colonoscopy showed that the anastomotic astium and colonic mucosa were normal.

LESSONS

Analysis of the case showed that computed tomography angiography is an important auxiliary examination for establishing the diagnosis of IMAVF and surgery is an effective treatment.

Massive Left-sided Congestive Colitis Due to Idiopathic Inferior Mesenteric Arteriovenous Malformation

Arteriovenous malformations (AVM) of the inferior mesenteric artery are rare. They may be primary (congenital or idiopathic) or secondary (acquired) after trauma or of iatrogenic origin. Of the abdominal AVM, the inferior mesenteric trunk is the least commonly involved. Most reported cases are of iatrogenic origin, resulting from colon surgery. Only 17 cases have been described and published in the literature. The objective of this work is to make known a case treated in our center. We present a case of 73-year old male, who came to the emergency service with symptoms of abdominal distension, pain lasting 48 hours along with months of diarrhoea. CT scan and an abdominal CT angiography showed a massive left-sided congestive colitis due to idiopathic inferior mesenteric arteriovenous malformation. In our case, the decision was to carry out the treatment in two stages. Embolisation was performed in the first stage in order to decrease the blood flow and the risk of intraoperative bleeding, followed by resective surgery of the affected colon.

Inferior mesenteric arteriovenous fistula

Arteriovenous fistula (AVF) involving the inferior mesenteric artery and vein is very rare with only 33 cases described in the literature and may be of congenital or acquired (iatrogenic or traumatic) or idiopathic etiology. The pathophysiology of AVF that acts as a left-to-right shunt has accounted for clinical signs and symptoms associated with ischemic colitis, portal hypertension, and heart failure. A low incidence and nonspecific clinical signs and symptoms such as abdominal pain, thrill and mass, lower and upper gastrointestinal bleeding make it difficult to establish a diagnosis of inferior mesenteric AVF. Diagnosis of inferior mesenteric AVF is usually established by radiological or intraoperative examination. We report a case of idiopathic inferior mesenteric AVF causing ischemic colitis in a 56-year-old man that was diagnosed preoperatively by multidetector computed tomography and angiography and successfully treated by surgical resection.

High-Flow Vascular Malformation in the Sigmoid Mesentery Successfully Treated with a Combination of Transarterial and Transvenous Embolization

Mesenteric high-flow vascular malformation can cause various clinical symptoms and demand specific therapeutic interventions owing to its peculiar hemodynamics. We report a case of high-flow vascular malformation in the sigmoid mesentery which presented with ischemic colitis. The main trunk of the inferior mesenteric vein was occluded. After partially effective transarterial embolization, transvenous embolization was performed using a microballoon catheter advanced to the venous component of the lesion via the marginal vein. Complete occlusion of the lesion was achieved. Combination of transarterial and transvenous embolization may allow us to apply endovascular treatment to a wider variety of high-flow lesions in the area and possibly avoid the bowel resection.

Acute massive congestive ischaemic colitis related to inferior mesenteric arteriovenous malformation

We report a very rare case of acute congestive ischaemic colitis of the left colon caused by brutal decompensation of an uncommon arteriovenous malformation (AVM) in the territory of the inferior mesenteric artery (IMA) in a 45-year-old male patient. The patient presented with severe abdominal pain in the left iliac fossa and abundant mucoid stools. The diagnosis of congestive colitis was made by optical colonoscopy but the full diagnosis of the responsible AVM in the IMA territory was made by contrast-enhanced multidetector CT scan combined with colour Doppler ultrasound. Two successive attempts at selective embolization failed to resolve the symptoms and finally, extensive surgery was necessary. The complete imaging findings of the case are presented and the characteristic features of uncommon AVMs and fistulas of the IMA territory are briefly reviewed.