Aneurysm rupture in median arcuate ligament syndrome leading to duodenal stenosis: A case report

Abstract

BACKGROUND

A 56-year-old female presented with acute abdominal pain due to a ruptured pseudoaneurysm associated with median arcuate ligament syndrome (MALS), a rare condition caused by the compression of the celiac artery by the median arcuate ligament (MAL), potentially leading to ischemia, aneurysm formation, and rupture.

CASE SUMMARY

Computed tomography revealed a retroperitoneal hematoma, celiac artery stenosis, and two aneurysms in the inferior pancreaticoduodenal artery. Hemostasis was achieved using transcatheter arterial embolization. However, 15 days after embolization, the patient developed duodenal stenosis, manifesting as gastric distension and nausea without abdominal pain. Endoscopy revealed mucosal edema and luminal narrowing of the duodenum. Conservative treatment was ineffective, and the patient underwent MAL transection and gastrojejunostomy. She recovered uneventfully, and follow-up at 4 months showed complete resolution of duodenal stenosis and no recurrence.

CONCLUSION

This case highlights the importance of the early diagnosis and multidisciplinary management of MALS.

Key Words: Median arcuate ligament syndrome; Retroperitoneal hemorrhage; Duodenal stenosis; Inferior pancreaticoduodenal artery aneurysm; Transcatheter arterial embolization; Case report

Core Tip: This case report describes a rare clinical course of median arcuate ligament syndrome (MALS) presenting with a ruptured aneurysm followed by duodenal stenosis after transcatheter arterial embolization. The patient required early surgical treatment, including gastrojejunostomy and decompression via median arcuate ligament transection. The combination of vascular and gastrointestinal complications highlights the importance of multidisciplinary management and timely intervention in patients with complex MALS.

INTRODUCTION

The median arcuate ligament (MAL) is a fibrous arch formed by fusion of the right and left crura of the diaphragm. It is located anterior to the aorta, at the level of the T12 vertebra, where the aorta passes through the diaphragm. The MAL plays a crucial role in supporting the diaphragm and protecting the aorta during the passage. However, in a few patients, the MAL can compress the origin of the celiac artery, resulting in a condition known as MAL syndrome (MALS). MALS was first reported in 1968 by Harjola and Lahtiharju[1]. Although considered a rare disease, previous reports have documented cases that were either asymptomatic or diagnosed only after rupture of an associated aneurysm[2-4]. A delayed diagnosis of MALS can lead to a decline in the quality of life. Aneurysm rupture can result in severe complications. Therefore, MALS is considered to be an important disease. Herein, we report a case of MALS diagnosed because of aneurysmal rupture that presented with a rare clinical course, including duodenal stenosis following hemostasis. This case is significant because it highlights a rare clinical course in which a ruptured aneurysm associated with MALS leads to secondary duodenal stenosis, ultimately requiring surgical intervention. Such sequences have been reported infrequently and may expand our current understanding of MALS-related complications.

CASE PRESENTATION

Chief complaints

A 56-year-old female presented with upper abdominal pain and cold sweats.

History of present illness

Three days before admission (day-3), she experienced spontaneous resolution of similar abdominal pain. On day 0, she returned to the emergency department with recurrent symptoms, prompting further evaluation.

History of past illness

She had no history of hypertension, diabetes, or other significant medical conditions.

Personal and family history

She had never smoked or consumed alcohol. No notable family history exists.

Physical examination

Her vital signs were stable, with a pulse rate of 90 bpm and a blood pressure of 136/84 mmHg. Abdominal distension was noted without tenderness.

Laboratory examinations

Laboratory data on day 0 revealed white blood cell 10070/μL, hemoglobin 10.5 g/dL, and C-reactive protein 2.26 mg/dL.

Imaging examinations

Contrast-enhanced computed tomography (CT) on day 0 showed a large retroperitoneal hematoma, smaller hematomas in the pelvic cavity (Figure 1A), stenosis at the origin of the celiac artery (Figure 1B), and two aneurysms in the inferior pancreaticoduodenal artery (Figure 1C).

Figure 1 Image of contrast-enhanced computed tomography. A: Contrast-enhanced computed tomography (CE-CT) showing a retroperitoneal hematoma, indicating arterial bleeding; B: CE-CT showing celiac artery stenosis (arrow), supporting the diagnosis of median arcuate ligament syndrome; C: CE-CT showing two aneurysms in the inferior pancreaticoduodenal artery (arrow), requiring intervention.

MULTIDISCIPLINARY EXPERT CONSULTATION

On day 0, the patient was reviewed by a multidisciplinary team, including gastroenterologists, interventional radiologists, and surgeons. We agreed to proceed with embolization to achieve hemostasis as the first-line intervention because of its minimally invasive nature and effectiveness in emergency hemorrhage control.

FINAL DIAGNOSIS

Retroperitoneal hemorrhage due to a ruptured pseudoaneurysm associated with MALS, complicated by post-embolization duodenal stenosis.

TREATMENT

On day 0, interventional radiology was performed to achieve hemostasis via an approach through the right femoral artery. Angiography revealed two aneurysms in the inferior pancreaticoduodenal artery (Figure 2A). The anterior inferior pancreaticoduodenal artery was embolized using four microcoils (Figure 2B). Additionally, angiography of the celiac artery revealed stenosis at its root, consistent with MALS findings. After transcatheter arterial embolization (TAE), no abdominal pain, signs of acute pancreatitis, or anemia were observed. The patient was discharged on day 8 after stabilization. On day 23, she was readmitted due to gastric distension and nausea. She did not experience any abdominal pain. A CT scan revealed a trend of hematoma reduction; however, gastric distension was observed without any dilation of the duodenum (Figure 3A and B). Gastric passage obstruction due to duodenal stenosis was suspected. Endoscopic observation revealed duodenal stenosis extending from the superior duodenal angle to the third portion of the duodenum. A standard upper endoscope cannot pass through the stenosis, an ultra-slim upper endoscope. The duodenal mucosa showed mild redness and edematous changes, but no mucosal damage such as erosion or ulcers was observed (Figure 3C and D). Despite the reduction of the retroperitoneal hematoma, duodenal stenosis occurred. We considered that the cause of this was not compression of the hematoma but edematous changes due to chemical inflammation of the hematoma. The stenosis was expected to be reversible. However, the stenosis worsened further, and no fluid passed through. Conservative treatment was continued for 12 days without improvement. Because the patient desired a quicker recovery, surgical treatment was decided, including MAL transection and gastrojejunostomy, on day 35.

Figure 2 Images of angiogram during interventional radiology. A: Angiography showing aneurysms in the inferior pancreaticoduodenal artery, confirming the bleeding source (arrow); B: Post-embolization angiography showing successful hemostasis with microcoils.

Figure 3 Duodenal stenosis following transcatheter arterial embolization on day 23. A: Computed tomography (CT) showing gastric distension without duodenal dilation after transcatheter arterial embolization; B: CT showing reduced retroperitoneal hematoma; C: Endoscopy showing edematous duodenal mucosa without ulceration; D: Endoscopic contrast showing stenosis in the third part of the duodenum (arrow).

OUTCOME AND FOLLOW-UP

The patient recovered uneventfully and was discharged 12 days postoperatively. At the 4-month follow-up, endoscopy showed full resolution of the duodenal stenosis (Figure 4) and no recurrence of the aneurysm.

Figure 4 Endoscopy at 4 months showing resolved duodenal stenosis after surgery.

DISCUSSION

MALS is a rare condition characterized by the compression of the celiac artery by the MAL, which can lead to gastrointestinal ischemia and, in some cases, aneurysm formation[5-8]. Many patients remain asymptomatic, aneurysms associated with MALS rupture, and present as emergencies[2-4]. Celiac artery compression by MAL has been reported in up to one-third of autopsy cases and in 6.7% of asymptomatic patients on CT imaging[9,10]. This finding may reflect, at least in part, the dynamic nature of celiac artery compression influenced by the respiratory phase, particularly expiration, which can exaggerate narrowing on imaging[10]. This suggests that many patients may be asymptomatic. Aneurysm formation is another consequence of celiac artery compression, often resulting from increased blood flow that compensates for gastrointestinal ischemia. A few patients with MALS have been diagnosed after the rupture[2-4]. In our case, the patient was diagnosed with an aneurysm rupture despite the absence of MALS-related abdominal symptoms prior to the event. The rupture of a pancreaticoduodenal artery aneurysm, which represents 2% of splanchnic aneurysm ruptures[11-13], is a clinical emergency in nearly 22% of cases and requires urgent treatment[14]. Treatment options for pancreaticoduodenal artery aneurysm rupture include surgical hemostasis and TAE, with TAE being the preferred choice due to its minimally invasive nature. However, TAE alone may not adequately control aneurysmal rupture. Hofmann et al[15] reported a case of MALS in which aneurysm rupture recurred after TAE. In our case, surgical splitting of the MAL was performed to correct abnormal blood flow. No postoperative aneurysm recurrence was observed. In this case, duodenal stenosis occurred 15 days after TAE. Nakayama et al[16] showed that three types of duodenal stenosis can occur after TAE. The acute phase was defined as within 1 week, the subacute phase was defined as > 1 week but within 1 month, and the chronic phase was defined as > 1 month. In that report, the median period between the onset of duodenal stenosis and TAE was 10 days, and duodenal stenosis occurred in 83% of cases in the subacute stage. In this case, it occurred 15 days after TAE in the subacute phase. Duodenal ischemia, mechanical compression due to hematoma, and duodenal fibrotic encasement have been reported as causes of this condition[17-19]. In our case, despite a reduction in the retroperitoneal hematoma, duodenal stenosis occurred. Additionally, the duodenal mucosa exhibited only edematous changes. Acute pancreatitis is a known complication of TAE. It is possible that inflammation of acute pancreatitis could extend to the surrounding tissues and result in duodenal stenosis. However, in the present case, there was no evidence of acute pancreatitis following TAE. Therefore, duodenal stenosis was suspected to have been caused by inflammation due to ischemia after TAE. Blood supply to the duodenum is primarily provided by branches of the superior mesenteric artery and the gastroduodenal artery, which form an interconnected arcade. This vascular arrangement helps maintain adequate perfusion even if one of the supplying vessels is compromised by TAE, thus reducing the likelihood of duodenal ischemia[20]. Although TAE reduced the blood supply to the duodenum, leading to edematous changes in the mucosa, it prevented complete ischemia. In previous reports, duodenal edematous changes after TAE improved with conservative treatment in most cases[16]. However, Kwon et al[17] reported that conservative treatment did not improve, and surgical intervention was performed on the 24^th day after TAE. Our patient required a long period for the improvement of duodenal stenosis. Therefore, we performed a gastrojejunostomy simultaneously with MAL transection. The edematous changes in the duodenal mucosa disappeared 4 months after surgery. In this case, the embolized artery was the inferior pancreaticoduodenal artery, which directly contributes to duodenal perfusion. Although the duodenum has rich collateral flow, embolization of this major arcade component may lead to localized ischemia or inflammation, predisposing the patient to duodenal stenosis[16,20]. Our case reinforces the idea that conservative treatment is often sufficient; a few patients may require timely surgical management. These findings suggest that patients diagnosed with MALS, particularly those presenting with aneurysmal rupture and persistent duodenal stenosis, may benefit from long-term vascular monitoring. When conservative measures fail, early surgical intervention may prevent recurrence and improve outcomes.

CONCLUSION

This case illustrates a rare but clinically important course of MALS, beginning with an arterial aneurysm rupture and progressing to duodenal stenosis after embolization. Early diagnosis, appropriate vascular and gastrointestinal monitoring, and timely interventions are essential. Further research is needed to establish optimal strategies for managing post-embolization complications of MALS, particularly regarding the timing and indications for surgical intervention.