Chronic pancreatitis is a multifactorial inflammatory syndrome in which repetitive episodes of pancreatic inflammation lead to exocrine and endocrine insufficiency. Pancreatic pseudocysts are considered one of the major complications of pancreatitis. Most of them are resolved spontaneously; however, if they produce symptoms like pain and jaundice or increase in size after 6 weeks, endoscopic or surgical management may be necessary to avoid complications.^[1,2] Hemorrhage is considered one of the most life-threatening complications of pseudocysts, with a reported incidence of 6%–17% and mortality of 12%–40%.^[3–7] They can fistulize to surrounding vessels, most frequently to splenic artery, gastroduodenal artery, portal vein, splenic vein, and superior mesenteric vein.^[8–10] Fistulization of superior mesenteric artery with a pancreatic pseudocyst is a rare entity with only two cases described in the literature.^[11,12] Nowadays, endovascular techniques (embolization with coils/glue, stent graft) are considered an efficacious treatment modality for such communications with low perioperative morbidity and mortality and high technical success rate.^[12,13] We report the case of a symptomatic male patient with hemorrhagic pseudocyst due to the presence of a fistula with superior mesenteric artery successfully managed endovascularly with stent graft deployment.

A 47-year-old Caucasian male patient presented at the emergency room of a peripheral hospital with abdominal pain for the last 24 hours. His medical history was remarkable for daily alcohol consumption for at least 10 years, recurrent episodes of alcohol-induced pancreatitis in the last 2 years, coronary artery disease that was managed by percutaneous coronary angioplasty in 2019, arterial hypertension, dyslipidemia, and current smoking. His medication was clopidogrel, statin, and ß-blocker. On clinical examination, the patient was hemodynamically stable, and the electrocardiography showed sinus rhythm. He suffered from abdominal pain located in the epigastrium with tenderness at deep palpation without peritonism radiating to the lumbar region. His bowel sounds were not pathological, and the digital rectal examination was negative for blood. Laboratory tests revealed normal levels of white blood cell count, hemoglobin, serum, and urine amylase but a slight increase of hepatic enzymes (SGOT 54 U/L, normal range 11-34 U/L) (SGPT 71 U/L, normal range 0-45 U/L)(Table 1) . The pain did not subside with intravenous administration of paracetamol, and a contrast-enhanced computed tomography (CT) was decided. The CT depicted parenchymal pancreatic calcification due to chronic pancreatitis, a round 50 mm mass behind the pancreatic head and uncinate process that was in contact with the superior mesenteric artery (SMA) and deviated it to the left.(Fig. 1) . The content of the sac was heterogeneous with hemorrhagic fluid signal intensity within. At the delayed phase of CT, a communication between SMA and the pseudocyst was noted with the presence of contrast agent within the pancreatic lesion(Fig. 2) . The patient was transferred to our tertiary institution for further evaluation and treatment. After consultation with the general surgeons of our hospital, an endovascular repair of the fistulized pseudocyst with SMA was decided since it was technically feasible. The mainstem of SMA was 70 mm long, the diameter was 9 mm in the proximal part and 7 mm in the distal part at the level of the fistula without any other anomaly of arterial wall. The patient was informed perioperatively for all possible adverse events and a written informed consent was obtained for endovascular repair. Operation was performed in a fully equipped operation theatre with a portable C-arm (Ziehm Vision RFD, Hybrid Edition, Nuremberg, Germany). Under general anesthesia, arterial access was gained through surgical cut down of the left brachial artery. After systemic heparinization (75 IU/kg), a 5Fr sheath was placed. A hydrophilic guidewire 0.035 inches (Radifocus, Terumo Corp, Tokyo, Japan) was advanced to the abdominal aorta. The 5Fr sheath was exchanged with a 7Fr 90-cm long sheath. An aortic angiography was performed which revealed the SMA orifice. SMA was successfully catheterized with a 100 cm long Bern catheter (Boston Scientific, Marlborough, USA) and Terumo guidewire was exchanged with a Rosenwire 260 cm long (Cook Medical, Bloomington, USA) to avoid any injury to SMA and its branches. Two balloon expandable stent grafts ICover (IVascular, Barcelona, Spain) 8×37 mm and 9×37 mm were deployed distally to proximally in the SMA to counteract size discrepancy of the artery(Fig. 3) . Total operation time was 62 minutes and the contrast amount was 80 ml. Postoperative period was uneventful, abdominal pain subsided and the patient was discharged on the fifth postoperative day under dual antiplatelet therapy for at least 3 months followed by a lifelong single antiplatelet regimen. Follow-up CT at 1 month revealed patent SMA covered stent with absence of communication and shrinkage of the pancreatic pseudocyst to 15 mm(Fig. 4) .

Patients with chronic pancreatitis may suffer from arterial complications such as arterial thrombosis from local compression of an artery from a pancreatic pseudocyst, arterial bleeding during percutaneous drainage of pseudocyst as well as arterial pseudoaneurysms.^[14] Fistulization of a pancreatic pseudocyst is a rare, life-threatening complication. If communication exists with surrounding vessels, pseudoaneurysm or hemorrhage within the pseudocyst can occur.‌^[12] Its incidence is low in patients with chronic pancreatitis; however, it is associated with high mortality.^[7,14] In a meta-analysis of 29 studies, the pooled incidence rate of pseudoaneurysms in chronic pancreatitis was 0.03%.^[13] In a retrospective analysis by Anand et al., pseudocyst and alcoholic pancreatitis were independent factors for pseudoaneurysm formation.^[15] The main pathophysiological mechanism is the proteolytic action of pancreatic enzymes in surrounding vessels resulting in vessel wall erosion and loss of their integrity.^[14] The splenic artery, gastroduodenal artery, and superior-inferior pancreaticoduodenal arteries are the most frequently involved with pancreatic pseudocysts.^[8,10] Fistulization of a pancreatic pseudocyst with SMA has been reported in only 2 cases in the literature. Bouassida et al. reported a patient presented with gastrointestinal bleeding due to erosion of a pancreatic pseudocyst in SMA with fatal outcome^[12], whereas Cowan et al. reported the first successful endovascular management of SMA pseudoaneurysm fistulized to pancreatic pseudocyst with deployment of polytetrafluoroethylene stent graft.^[11] If deployment of a stent-graft is not feasible due to technical and anatomical issues in the presence of pseudoaneurysm, endovascular embolization is an alternative minimal invasive technique. Its efficacy has been demonstrated in a meta-analysis where the pooled technical success rate was 97% and clinical success rates at ≤3 months, 3-12 months, and >12 months were 82%, 86%, and 88%, respectively.^[14] Additionally, endoscopic ultrasound-guided endovascular therapy is a novel, minimally invasive tool for the management of gastrointestinal bleeding that involves the placement of thrombotic materials or coils in the targeted vessels, representing a new area of development with limited results.

Fistulization of pancreatic pseudocyst with the superior mesenteric artery is a rare entity that, if left untreated, can lead to devastating consequences. The diagnosis is often delayed due to its infrequent occurrence and clinical presentation. Imaging with computed tomography angiography can diagnose hemorrhagic complications of pseudocysts. Regarding therapeutic strategies, endovascular repair, whenever it is feasible as a minimally invasive technique with its armamentarium (embolization, stent graft), can manage such pathologies with low perioperative morbidity and mortality.

Written informed consent was provided by the patient.

The authors have no conflicts of interest to declare.

The authors declare that this study has received no financial support.

K.T., K.S., and G.C.: primary idea, writing, literature review. D.K. and N.S.: supervision