Superior mesenteric artery syndrome revealing a primary adenocarcinoma of the jejunum: a case report and literature review

¹Department of Anesthesiology and Critical Care, Faculty of Medicine and Pharmacy of Agadir, University Ibn Zohr, Agadir, Morocco, ²Department of Radiology, Faculty of Medicine and Pharmacy of Agadir, University Ibn Zohr, Agadir, Morocco

^&Corresponding author
Youssef Hadzine, Department of Anesthesiology and Critical Care, Faculty of Medicine and Pharmacy of Agadir, University Ibn Zohr, Agadir, Morocco

Introduction    

Superior mesenteric artery syndrome is a rare condition in which the third portion of the duodenum is compressed between the abdominal aorta and the superior mesenteric artery, because of a reduced angle formed by these two vessels. Its estimated incidence ranges from 0.2% to 0.78% [1]. This abnormality can be congenital or acquired in cases of rapid and significant weight loss due to malabsorption syndrome such as celiac disease, malignant disease or others. The clinical presentation comprises nonspecific symptoms. Diagnosis is confirmed mostly by a contrast-enhanced Computerized tomography (CT) scan, which allows measurement of the aortomesenteric angle and the distance between the two vessels. The treatment of this condition can be divided into two parts: the management of the bowel obstruction, which can be either conservative or surgical and correcting undernutrition and electrolyte disorders. We report a case of a 40-years-old woman with celiac disease, who presented with superior mesenteric artery syndrome, revealing the presence of a primary adenocarcinoma of the jejunum. The patient was already at risk of developing SMAS due to her celiac disease and her digestive symptoms can be explained by this syndrome. However, the discovery of the jejunal tumor added another risk factor for SMAS and could also explain the intestinal obstruction on its own. In the literature, we found two similar cases of primary adenocarcinoma of the small intestine revealed by a superior mesenteric artery syndrome [2,3].

Patient and observation     

Patient information: a 40-year-old woman, diagnosed with celiac disease for one year based on duodenal biopsy and placed on a gluten-free diet with poor compliance, was admitted to the intensive care unit due to hypovolemic shock resulting from an upper gastrointestinal obstruction syndrome.

Clinical findings: for the past 20 days, the patient had a history of bilious vomiting, nausea and epigastric pain, along with a deterioration in her general condition and rapid weight loss of 8 kg. Prior to this acute presentation, she had endorsed over 5 months of abdominal pain and nausea that were not alarming for the patient and had not been investigated. The patient's Body mass index (BMI) remained within norms at 21 kg/m². Nevertheless, the patient went from her baseline weight of 65 kg to 57 kg in just 3 weeks. Physical examination revealed a lethargic patient with hypotension at 80/60 mmHg, tachycardia at 130 BPM and anuria. Abdominal examination identified abdominal distension and an epigastric tenderness. Blood tests showed white blood cells count at 15959/mm³, hemoglobin at 11,3 g/dL, acute renal failure with urea at 2,1 g/L and creatinine 12 mg/L, hypokalemia at 3,0 mmol/L, hyponatremia at 130 mmol/L and hypoalbuminemia at 27 g/L.

Diagnostic assessment: contrast-enhanced abdominal computed tomography (CT) scan indicated an acute upper gastrointestinal obstruction secondary to a superior mesenteric artery syndrome, with a reduced angle measured at 15.9° and a distance of 6.40 mm between the aorta and the superior mesenteric artery. An image of sausage-shaped mass suggestive of secondary intestinal intussusception of the proximal jejunum was also observed (Figure 1).

Therapeutic intervention: after receiving isotonic saline infusion, the patient's hemodynamic status stabilized. She was then transferred to the operating room for an exploratory laparotomy. Surgical exploration revealed intestinal intussusception secondary to a jejunal tumor. Consequently, a limited jejunal resection and end-to-end primary small bowel anastomosis was performed (Figure 2). Anatomopathological examination of the surgical specimen revealed an infiltrating moderately differentiated adenocarcinoma of the jejunum, developing on a subtotal villous atrophy induced by celiac disease.

Follow-up and outcomes: post-operative follow-up proceeded without any complications. Water and electrolytes disturbances have been corrected. The nasogastric tube placed pre-operatively to relieve the distension was kept in place, and a naso-jejunal tube was added during the surgery to facilitate enteral feeding, combined with parenteral nutrition in order to reach daily calorie targets. The patient's condition improved markedly, with regression of abdominal pain and disappearance of vomiting. She was transferred from the intensive care unit to the visceral surgery unit after 5 days post-operatively.

Informed consent: informed written consent was obtained from the patient to publish this work.

Discussion     

Superior mesenteric artery syndrome, also known as Wilkie's syndrome, is defined as an extrinsic upper gastrointestinal obstruction due to a vascular abnormality. This syndrome is characterized by a reduced angle between the abdominal aorta and the superior mesenteric artery, resulting in the compression of the organs passing between these two vessels, such as the third part of the duodenum. It more commonly affects young patients and the female gender [4].

The etiology of the SMAS can be congenital or acquired in cases of malignant pathology or severe malabsorption leading to cachexia. Normally, the fatty tissue located in the aorto-mesenteric space maintains an aorto-mesenteric angle between 25° et 60° and an aorto-mesenteric distance between 10 and 28 mm [5]. However, rapid weight loss can reduce the fatty tissue, decreasing the aorto-mesenteric angle and subsequently compressing the small bowel. Therefore, all causes of weight loss, such as malabsorption syndrome, cancerous diseases, tuberculosis cachexia and severe burns, are considered as triggering factors. There are also other factors, like the reduction of scoliosis, hyperlordosis or cerebral palsy, which can be responsible for the occurrence of superior mesenteric artery syndrome [6]. Nevertheless, there are cases of SMAS where none of these triggering factors are present.

The clinical presentation of superior mesenteric artery syndrome is variable and non-specific. Most commonly, it presents as an upper gastrointestinal obstruction syndrome with symptoms such as abdominal pain, nausea, bilious vomiting, abdominal distension and in severe cases, dehydration and denutrition, potentially leading to hypovolemic shock. The diagnosis is confirmed through radiologic studies, such as barium-enhanced radiographs that reveal duodenal distension which is a sign of upper gastrointestinal obstruction. However, abdominal CT with contrast, which allows measurement of the aorto-mesenteric angle and the distance between the two vessels, is the primary diagnostic tool [5,6].

In the present case, the patient had celiac disease, an auto-immune intestinal disorder triggered by gluten ingestion. Its physiopathology involves an immune and inflammatory response that leads for the destruction of intestinal villi and results in severe malabsorption [7,8]. In addition, celiac disease patients tend to have an increased risk of malignancies, such as cancers of the gastrointestinal tract and intestinal lymphomas. The risk increases further when the Gluten-free diet (GFD) is not well managed by patients, exposing them to chronic intestinal inflammation [9].

Our patient's particularity lies in the fact that, due to her celiac disease, she presents a terrain highly conducive to the development of digestive cancer and the combination of the two makes her a candidate for SMAS. Indeed, the symptoms of upper gastrointestinal obstruction prompted an abdominal CT scan, which showed intestinal intussusception secondary to a jejunal tumor associated with a reduced angle between the superior mesenteric artery and the abdominal aorta.

In the literature, we found two other cases of malignant jejunal tumor revealing by superior mesenteric artery syndrome (Table 1) [2,3]. In both cases, the clinical symptoms closely resembled those observed in our patient. The common presentation was an upper gastrointestinal obstruction syndrome, without any specific clinical signs pointing to the etiology of the syndrome. Also, for the two cases in the literature, abdominal CT scans played a pivotal role in diagnosing superior mesenteric artery syndrome.

Unlike the case described by Sakamoto et al. in 2023 [2], in the case reported by Sun et al. in 2016 [3], the jejunal tumor was not visualized on abdominal CT and was only diagnosed later during exploratory laparotomy, prompted by the failure of conservative SMAS treatment. Much like our patient, the small intestine tumor did not figure on the abdominal CT and was only discovered during surgery for secondary intestinal intussusception. Besides, all reported cases involved primary small intestine adenocarcinoma and were treated through surgical resection.

Finally, the treatment of the superior mesenteric artery syndrome can be divided into two parts. On one hand, there is the duodenal decompression, which can be achieved either through conservative medical methods or surgical intervention. Medical treatment is the initial approach, involving the placement of a nasogastric tube for decompression. But in case of treatment failure, surgical intervention becomes necessary, with options such as gastrojejunostomy or a duodenojejunostomy. On the other hand, the second aspect of the treatment focuses on correcting denutrition and dehydration by using a nasojejunal feeding tube and addressing associated hydroelectrolytic disorders.

In the present case, the discovery of the tumor indicated a partial jejunal resection with jejunal termino-terminal anastomosis, associated with medical treatment for SMAS. The patient had a nasogastric tube in continuous suction for the duodenal decompression, associated with a nasojejunal feeding tube. The outcome of the treatment was favorable, with an improvement in the patient's clinical symptoms.

Conclusion     

Wilkie's syndrome or superior mesenteric artery syndrome, is a rare condition characterized by a reduced angle between the abdominal aorta and the superior mesenteric artery, resulting from the regression of adipose tissue between the two vessels. This leads to upper gastrointestinal occlusion. When acquired, it often occurs in patients undergoing rapid weight loss induced by a malabsorption syndromes or malignant diseases. In this case, the patient had celiac disease, that predisposed her to both digestive cancer and superior mesenteric artery syndrome. During the exploration of an upper bowel obstruction syndrome, a SMAS was radiological found associated with an intestinal intussusception secondary to a small bowel tumor. The histological study of the surgical piece revealed primary adenocarcinoma of the jejunum.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All the authors contributed to this work. They read and approved the final version of this manuscript.

Table and figures     

Table 1: literature cases of adenocarcinoma revealed by a superior mesenteric artery

Figure 1: contrast-enhanced abdominal computarized tomography (CT)

Figure 2: peri-operative view of the surgical resection specimen

References