Diagnostic value of upper gastrointestinal imaging for duodenal webbing in adults: A case report

Abstract

BACKGROUND

Duodenal web is a rare congenital malformation, exceedingly uncommon in adults, and often misdiagnosed due to the subtle imaging features.

CASE SUMMARY

By analyzing the clinical diagnosis process and various imaging findings of a patient from our institution, this case report emphasizes the necessity of upper gastrointestinal series in diagnosing duodenal webs, outlines its typical radiographic features, and provides a literature review on the etiology, clinical presentation, and management of this condition.

CONCLUSION

This case report emphasizes the necessity of upper gastrointestinal series in diagnosing duodenal webs.

Key Words: Duodenal web; Upper gastrointestinal imaging technology; Misdiagnosis; Medical imaging; Case report

Core Tip: Duodenal web is a rare congenital malformation causing intestinal obstruction, primarily seen in newborns but also possible in adults. This case report highlights a 27-year-old male with misdiagnosed duodenal web due to atypical imaging results. Upper gastrointestinal imaging ultimately revealed characteristic features leading to the correct diagnosis. This emphasizes the importance of recognizing specific imaging manifestations for accurate preoperative diagnosis and suggests that clinicians should consider duodenal web in adult patients with unexplained recurrent pancreatitis. Comprehensive examinations are crucial to avoid missed diagnoses in such cases.

INTRODUCTION

The duodenal web, a membranous or web-like protrusion within the lumen of the duodenum, frequently results in varying degrees of intestinal obstruction, particularly in the descending segment of the duodenum. This congenital gastrointestinal malformation commonly coexists with other congenital anomalies, falling within an incidence range of 1 in 10000 to 1 in 40000 individuals[1]. Its etiology is postulated to stem from incomplete intestinal vacuolation during the embryonic period[2], which explains its higher prevalence in neonates and infants compared to the exceedingly rare occurrence in adults[3,4]. Clinically, the duodenal web presents with a spectrum of nonspecific symptoms, including epigastric pain, nausea, abdominal distension, and weight loss[5]. These manifestations can be confounding, as they may overlap with or be overshadowed by other comorbid conditions, contributing to diagnostic challenges and the potential for misdiagnosis or missed diagnoses. In April 2024, our institution encountered a unique case of an adult patient presenting with a variant form of duodenal web, characterized by a windsock-shaped configuration with a central perforation. Throughout the diagnostic trajectory, this patient experienced multiple misdiagnoses due to the ambiguity of their clinical presentations and the non-specific findings on computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/CT (PET/CT) scans. This underscores the complexity and nuances involved in accurately diagnosing the duodenal web, particularly in adults.

CASE PRESENTATION

Chief complaints

A 27-year-old male presented with a suspected duodenal mass lasting for over five months. Six months prior, he began experiencing episodic upper abdominal pain after meals, without associated symptoms such as nausea, vomiting, or fever.

History of present illness

He returned for follow-up on April 16, 2024, where gastroscopy showed duodenal obstruction with food retention, prompting hospital admission with a working diagnosis of duodenal mass.

History of past illness

On December 3, 2023, gastroscopy revealed chronic non-atrophic gastritis, a posterior duodenal bulb lesion, and gastric retention.

Personal and family history

The patient denied any significant medical history, including hypertension, infectious diseases, or allergies. There was no history of trauma, surgery, or exposure to environmental hazards. His vaccination and blood transfusion history were unknown.

Physical examination upon admission

The patient’s vital signs were stable: (1) Temperature 36.4 °C; (2) Pulse 61 bpm; (3) Respiration 18 bpm; and (4) Blood pressure 115 mmHg/64 mmHg. His general condition was unremarkable, with normal mental status, nutrition, and ambulation. There were no signs of systemic illness or abnormal physical findings, including no lymphadenopathy, skin abnormalities, or neurological deficits. Cardiopulmonary examination showed clear breath sounds bilaterally and normal heart rate and rhythm, with no murmurs. Abdominal examination revealed no tenderness, and no organomegaly was noted.

Imaging examinations

Gastroscopy, December 15, 2023: Chronic non-atrophic gastritis, primarily affecting the gastric antrum, along with post-bulbar duodenal elevated lesion of indeterminate nature and gastric stasis.

CT scan of the abdomen (Figure 1), December 5, 2023: Suspected lesion within the lumen of the descending duodenum, without excluding the possibility of ectopic pancreas or other neoplastic lesions.

Figure 1 Computed tomography imaging. A: It Shows a circular thickening of the duodenal wall in a mass-like soft tissue density on plain scan; B and C: Demonstrate circular thickening and uniform enhancement of the duodenal wall during the enhanced arterial phase, with an enhancement level slightly approaching pancreatic density, which can be easily misdiagnosed as annular pancreas. Upon closer inspection, a double-lumen shadow can be observed; D, E, and F: They decreased enhancement in the delayed phase, with the lesion appearing as isodense or slightly hypodense.

Gastroscopy (Figure 2), April 16, 2024: Duodenal obstruction with food stasis.

Figure 2 Magnetic resonance imaging. A: It Shows slight thickening of the duodenal wall with strip-like structures visible inside on T2-weighted imaging with fat saturation; B: Demonstrates no significant increase in diffusion-weighted imaging signal; C, D, E, and F: They show strip-like enhancement within the duodenal lumen on enhanced imaging, suggesting a benign lesion. The possibility of duodenal mucosal prolapse is considered.

MRI of the abdomen (Figure 3), April 21, 2024: Mild thickening was observed in the wall of the descending duodenum, suggestive of benign pathology. There is a possibility of duodenal mucosal prolapse; differentiation from neoplastic lesions is necessary.

Figure 3 Conventional gastroscopic images: Conventional gastroscopy reveals no deformation of the duodenal bulb, with a velvety appearance of the mucosa and no ulcers observed. In the upper part of the descending duodenum, the mucosa appears spherical and can change shape and flatten with intestinal peristalsis. Thickening of the mucosa in the descending duodenum: Ectopic pancreas? Narrowing and deformation of the descending duodenum.

PET/CT scan of the abdomen (Figure 4), April 23, 2024: Uneven thickening of the mucosal wall in the proximal descending duodenum is observed. Both initial and delayed imaging phases show no significant increase in metabolic activity, suggesting a benign lesion, possibly duodenal mucosal prolapse.

Figure 4 Positron emission tomography/computed tomography imaging. Positron emission tomography/computed tomography shows uneven thickening of the mucosal wall in the upper part of the descending duodenum. Both the initial and delayed scans indicate no significant increase in metabolic activity, suggesting a benign lesion (possibly duodenal mucosal prolapse).

Upper gastrointestinal radiography (Figure 5), April 25, 2024: Localized stenosis was noted in the upper portion of the descending duodenum. A saccular intraluminal protrusion is visible below, filled with contrast medium, showing clear boundaries and a distinct demarcation from the adjacent normal intestinal mucosa. A circular lucent line is evident. The saccular structure demonstrates contractility and peristalsis, showing the characteristic "windsock" sign.

Figure 5 Upper gastrointestinal imaging. The images show localized narrowing of the luminal cavity in the upper part of the descending duodenum. Below this narrowing, a sac-like intraluminal protrusion (indicated by the orange arrow) is visible, filled with contrast agent, with clear boundaries and a distinct separation between the sac and the surrounding normal intestinal mucosa. A circular lucent line is observable. The sac-like protrusion exhibits contractility and motility, presenting a typical "windsock" sign (most evident in C).

FINAL DIAGNOSIS

Subsequent upper gastrointestinal radiography suggests the possibility of a duodenal web.

TREATMENT

The patient presented to our hospital on December 3, 2023. Gastroscopy revealed: (1) Chronic non-atrophic gastritis, primarily affecting the gastric antrum; (2) Post-bulbar duodenal elevated lesion of indeterminate nature; and (3) Gastric stasis. Symptoms were alleviated after conservative treatment (specifics unknown). The patient returned for a follow-up visit to our hospital. On April 16, 2024, gastroscopy was performed, showing duodenal obstruction with food stasis. The patient was admitted to the hospital with a diagnosis of "duodenal mass" based on outpatient evaluation. Subsequent upper gastrointestinal radiography suggests the possibility of a duodenal web.

OUTCOME AND FOLLOW-UP

Given that the patient's clinical presentation is not severe, manifesting as episodic upper abdominal pain, surgical intervention was not pursued at this time. A clinical recommendation is for follow-up observation with upper gastrointestinal radiography in 3-6 months to monitor changes in the lesion.

Literature Review

Obstruction during the intestinal recanalization in early embryonic development can result in duodenal atresia or stenosis, with an incidence rate of approximately 0.05% to 0.14%[6]. This condition is more common in low-birth-weight infants and often associated with other congenital malformations. Duodenal web malformation, a form of duodenal atresia or stenosis, is characterized by a diaphragm within the intestinal lumen, which may be completely closed, have a central opening, or form a membranous web. Among the various forms of duodenal atresia or stenosis, membranous atresia and stenosis are the most common (41% to 75%)[2]. Duodenal web (diaphragm) malformation primarily primarily presents as upper gastrointestinal obstruction symptoms, such as vomiting after feeding in infants. Membranous stenosis may sometimes present with mild symptoms due to intermittent vomiting, leading to a delayed diagnosis until school age, but it is rare in adults[6].

Unlike congenital duodenal atresia, the fibrous diaphragm of a duodenal web has one or more central or eccentric openings, allowing some food to pass through. With intestinal movement and the gravitational effect of food residues, the fibrous diaphragm is stretched and gradually forms a saccular pouch (also known as a "windsock"), which can extend up to the distal duodenum. Duodenal webs are diverse and influenced by various factors such as their location, shape, and opening conditions[5]. Statistically, 85% to 90% of duodenal webs are located in the descending portion of the duodenum, while a minority are found in the horizontal or ascending portions. The opening size of duodenal webs ranges from 2 mm to 10 mm, and it is usually a single opening. These factors variably affect the symptoms and severity of duodenal obstruction and also determine the age of onset[4,7]. In the present case, the duodenal web is located in the descending portion of the duodenum, near the opening of the duodenal papilla, with a perforated web allowing slow passage of food through into the distal duodenum. As the patient ages, the demand for solid foods results in slower passage through the opening, and retained food stretches the web into a saccular pouch.

The primary clinical manifestation of the duodenal web is duodenal obstruction, and it may also present as recurrent episodes of pancreatitis[4]. This condition is associated with Down's syndrome, intestinal malrotation[8], and annular pancreas. In this case, the main clinical presentation of the patient with duodenal web was episodic upper abdominal pain without nausea, vomiting, mucous or bloody stools, or any other complications. Therefore, surgical intervention was not performed at this time, and the patient is under follow-up observation. If combined with intestinal malrotation, which is rarer, the patient may experience dilation of the pancreatic duct, possibly due to high intestinal pressure resulting from duodenal obstruction and a history of pancreatitis.

The diagnosis of the duodenal web primarily relies on imaging examinations such as abdominal X-ray, upper gastrointestinal radiography, and CT or MRI. Among these, upper gastrointestinal radiography is a crucial diagnostic tool, as it can directly reveal the morphology, location, and relationship of the duodenal web with surrounding structures. The duodenal web appears as a "windsock" sign on upper gastrointestinal radiography and as a "double lumen" sign on CT or MRI. Some associated conditions, such as acute pancreatitis, can also be visualized by imaging. A vertical abdominal plain film sometimes shows dilated, air-filled fluid levels in the stomach and the first segment of the duodenum, known as the "double bubble" sign. Due to obstruction leading to the retention of food residues, mixed T2-weighted imaging (T2WI) hyperintense cystic lesions or layered changes within the duodenal lumen can also serve as distinguishing features of this disease. Duodenal web in adults is often difficult to diagnose preoperatively; the possibility of this condition should be considered if duodenal obstruction is detected during a barium meal examination or if endoscopy cannot access the distal duodenum. Therefore, for patients suspected of having a duodenal web, such examinations should be performed as early as possible to confirm the diagnosis and provide a basis for subsequent treatment planning.

In terms of treatment, conservative management, such as adjusting the diet to reduce solid food intake and increase liquid food intake, can be adopted for patients with asymptomatic or mildly symptomatic duodenal web to alleviate food retention and stretching of the web in the duodenum. However, for patients with obvious symptoms that affect quality of life or those with complications, surgical intervention should be considered. Surgery aims to excise or repair the duodenal web and restore intestinal patency. For adults with duodenal web without severe complications, partial web excision and duodenal plasty are recommended. For patients with concurrent peptic ulcers, surgeries to treat the ulcer, such as vagotomy and drainage procedures, should also be performed[9].

DISCUSSION

The Duodenal web (Figure 6) is an extremely rare disease, generally believed to be formed by the local residual diaphragms or web-like structures in the intestinal tube developing into the cavity. These structures gradually enlarge under the long-term effects of intestinal peristalsis, ultimately forming a structure similar to a windsock, composed of mucosa and submucosa but lacking muscular tissue. Its center often contains a small hole connected to the duodenal atresia[1].

Figure 6 Schematic illustrations of duodenal web (membranes). A: It Shows a complete membrane (indicated by the blue arrow), which signifies duodenal atresia; B: Displays a membrane with a perforation, indicating duodenal stenosis; C: Presents a variant pattern of duodenal web: The membrane within the intestinal lumen extends toward the distal end, appearing like a "windsock", and the web may have a perforation or be without one.

Cases of the duodenal web are mostly reported as individual instances, with the majority occurring in infants and children. The degree of obstruction is related to the size of the central hole. While this disease can also occur in adults aged 30 years to 40 years, and even in the elderly up to 82 years of age, adult cases are less frequently reported. This study provides valuable clinical insights for the diagnosis and management of such rare cases in adults. Most cases (85%-90%) are located in the second part of the duodenum (D2), with symptoms manifesting as duodenal obstruction or recurrent episodes of pancreatitis when occurring near the ampulla. Upper gastrointestinal radiography reveals a "windsock" sign, while CT and MRI show a "double lumen" sign. In reality, due to the retention of food residues caused by obstruction, mixed T2WI hyperintense cystic lesions or layered changes within the duodenal lumen can also serve as distinguishing features of this disease.

Studies have shown that 20%-30% of patients with duodenal atresia also have congenital heart disease; it can also be accompanied by an annular pancreas. Congenital duodenal obstruction can be complete or incomplete and must be differentiated from endogenous or exogenous lesions. Endogenous lesions primarily include duodenal atresia or duodenal web, while exogenous lesions include preduodenal portal vein, duodenal duplication, malrotation with Ladd's bands, and annular pancreas[6,8,10], and superior mesenteric artery syndrome. On CT, it must be differentiated from intraluminal duplication cysts of the duodenum. The former appears as a contrast-filled cystic high-density lesion on upper gastrointestinal radiography and as mixed T2WI hyperintense cystic lesions or layered changes on MRI, while the latter appears as a filling defect on upper gastrointestinal radiography and as a homogeneously hyperintense T2WI lesion on MRI.

Due to the proximity to surrounding tissues and organs, patients with duodenal web are prone to complications such as pancreatitis and intestinal obstruction. One study reported[10] that after eating semi-liquid foods, the dilated and enlarged cystic sac may block the opening of the duodenal papilla, leading to obstructed drainage and subsequently inducing acute pancreatitis. On the other hand, food in the cystic sac can slowly pass through the opening, and when the duodenal papilla is no longer blocked, pancreatitis can be alleviated.

CONCLUSION

In the diagnostic and treatment process of the patient in this case, upper gastrointestinal radiography provided strong evidence for the diagnosis. In summary, the duodenal web exhibits relatively typical imaging features. Recognizing these characteristic manifestations allows for a definitive preoperative diagnosis. Congenital duodenal web in adults is also one of the rare causes of acute pancreatitis. For patients with recurrent pancreatitis without an identifiable cause and a history of other developmental malformations, clinical attention should be paid to completing endoscopic examinations, upper gastrointestinal radiography, CT, and other examinations to avoid missed diagnoses.