Encapsulating peritoneal sclerosis: a three-case series highlighting diagnostic challenges and surgical managements

Abstract

Background:

Encapsulating peritoneal sclerosis (EPS) is a rare and heterogeneous fibro-inflammatory disorder of the peritoneum characterized by progressive formation of a dense fibrocollagenous membrane that envelopes and constricts the small bowel. Its protean clinical manifestations frequently overlap with other causes of intestinal obstruction, making timely diagnosis a persistent clinical challenge.

Case Presentations:

We report three cases of idiopathic EPS presenting with varying degrees of bowel obstruction and radiologic features initially suggestive of internal herniation, adhesive small-bowel obstruction, and intermittent closed-loop obstruction. All patients demonstrated dense adhesions or fibrous encapsulation intraoperatively, despite the absence of traditional risk factors such as peritoneal dialysis (PD) or abdominal tuberculosis (TB). CT findings aided early suspicion but lacked sufficient specificity to establish a preoperative diagnosis, underscoring the indispensable role of surgical exploration. Each patient underwent laparotomy with adhesiolysis and decapsulation, tailored to the extent of disease, with favorable postoperative outcomes.

Conclusion:

These cases illustrate the diagnostic complexity of EPS and reinforce that operative intervention remains the definitive means of both confirming the diagnosis and restoring bowel function once fixed obstruction or encapsulation has developed. Our series emphasizes the importance of maintaining EPS in the differential diagnosis of unexplained small-bowel obstruction, even in the absence of conventional predisposing conditions, and highlights the need for heightened clinical vigilance to prevent delays in management.

Introduction

Encapsulating peritoneal sclerosis (EPS), also referred to as abdominal cocoon syndrome (ACS), is among the most elusive and diagnostically challenging causes of small-bowel obstruction. The condition is characterized by the progressive development of a dense fibrocollagenous membrane that envelops and constricts the small intestine, producing a spectrum of pathology that ranges from subtle inflammatory changes to complete encasement within a rigid, cocoon-like sac. Despite its striking intraoperative appearance, EPS remains exceptionally rare, with our understanding of its epidemiology derived almost exclusively from isolated case reports and small clinical series. While idiopathic EPS represents only a minority of presentations, secondary forms are more commonly associated with established risk factors such as PD, chronic peritoneal inflammation, and certain historical pharmacologic exposures. The diagnostic process is particularly challenging because early symptoms including abdominal pain, anorexia, nausea, vomiting, weight loss, malnutrition, and altered bowel habits are nonspecific and overlap extensively with more many surgical conditions. Internal hernia, adhesive small-bowel obstruction, and intermittent closed-loop obstruction frequently masquerade as EPS, often delaying recognition. Although cross-sectional imaging, particularly computed tomography (CT), may demonstrate features such as clustered small-bowel loops or a thickened encasing membrane, these findings may be subtle or overshadowed by radiologic signs suggestive of alternative diagnoses. Consequently, many cases remain unsuspected until operative exploration, which continues to serve as the definitive means of diagnosis. In this paper, we describe three cases of idiopathic EPS, each occurring in patients without traditional predisposing factors of EPS. Together, these cases highlight the formidable diagnostic challenges posed by EPS, illustrate the limitations of preoperative imaging in distinguishing it from other obstructive pathologies, and underscore the essential role of laparotomy with adhesiolysis and decapsulation in re-establishing bowel function. By presenting these cases, we aim to heighten clinical awareness of this rare disorder and emphasize the critical importance of early recognition and timely surgical management.

HIGHLIGHTS

• Encapsulating peritoneal sclerosis (EPS) is a rare cause of small bowel obstruction.

• EPS, which mimics other abdominal conditions, is often diagnosed surgically.

• ⁠Early recognition & management prevent ischemia, perforation, and poor outcomes.

Methodology

This retrospective case series describes three patients diagnosed with EPS. The study was conducted at King Fahad Hofuf Hospital and Prince Saud Bin Jalawy Hospital, both located in Al-Ahsa, Saudi Arabia. Adults aged 18 years or older who exhibited characteristic CT findings, intraoperative evidence, or histopathologic confirmation of EPS within the preceding 10 years in Al-Ahsa were included. Patients younger than 18 years of age or those without confirmatory diagnostic evidence of EPS during the same time frame were excluded. Clinical, laboratory, and imaging data were independently extracted by two authors from medical records. According to institutional policy, ethical approval was not required for this case series; however, written informed consent for publication was obtained from all patients.

Case presentation 1

Clinical presentation

A 77-year-old Saudi man with a background of diabetes mellitus, hypertension, and ischemic heart disease presented with acute abdominal pain accompanied by repeated episodes of vomiting. On arrival, he was conscious, alert, and fully oriented. His vital signs were stable, and abdominal examination demonstrated a soft, non-tender, and lax abdomen without guarding or distension. Laboratory investigations were unremarkable.

Radiological findings

A non-contrast CT scan of the abdomen demonstrated markedly dilated small bowel loops, measuring up to 4 cm in diameter, with multiple air–fluid levels. A distinct transition zone was noted in the right mid-abdomen. No obstructing lesion, bowel ischemia, or perforation was identified.

Management and outcomes

Given the imaging findings and ongoing symptoms, the patient underwent an exploratory laparotomy on the day of admission. Intraoperatively, extensive small bowel encapsulation was observed, with dense adhesions surrounding multiple segments of bowel (Fig. 1). Adhesiolysis was meticulously performed, resulting in complete release of the entrapped loops. Peritoneal biopsies were obtained intraoperatively for mycobacterial culture, and all results returned negative, effectively excluding abdominal TB. The patient recovered uneventfully and was discharged 5 days later in good condition. At a scheduled clinic visit 2 weeks after discharge, he reported complete resolution of symptoms. Physical examination was unremarkable, his wound had healed well, and no postoperative complications were identified.

Figure 1.

Intraoperative image showing small bowel loops encapsulated within a thick fibrous membrane, Case 1.

Case presentation 2

Clinical presentation

A 37-year-old Indian man with no prior medical or surgical history presented with a 20-day history of intermittent epigastric pain accompanied by nausea and repeated episodes of food-containing vomiting. He denied constipation, diarrhea, weight loss, or other systemic symptoms. He reported an earlier evaluation at another hospital, where he was discharged with symptomatic treatment. On examination, he appeared well and hemodynamically stable. His abdomen was mildly distended with localized epigastric tenderness but no peritoneal signs. Laboratory investigations were within normal limits.

Radiological findings

A contrast-enhanced CT scan of the abdomen demonstrated a mid-abdominal trans-mesenteric hernia associated with segmental small bowel obstruction in a configuration consistent with a closed-loop obstruction.

Management and outcomes

The patient was taken for exploratory surgery, where intraoperative findings revealed markedly dilated distal jejunal and proximal ileal loops surrounded by dense adhesions and a thick-walled encapsulation (Figs 2 and 3). A mildly inflamed appendix was also identified and removed via appendectomy. Limited adhesiolysis was performed to release the obstructed segments. During dissection, an iatrogenic small bowel enterotomy occurred and was immediately repaired. Intraoperative peritoneal biopsies were submitted for TB culture, which subsequently returned negative. On postoperative day three, the patient developed recurrent vomiting, prompting placement of a nasogastric tube (NGT) for decompression. He subsequently exhibited localized surgical site tenderness with mild leukocytosis. An infected seroma was identified at the incision site, drained, and managed with regular wound dressing. His clinical status gradually improved, and he was discharged in stable condition 2 weeks after admission. At his scheduled follow-up clinic visit 2 weeks after discharge, he reported continued recovery with no further complications.

Figure 2.

Adhesive band identified intraoperatively, causing focal external compression, Case 2.

Figure 3.

Coronal contrast-enhanced CT image showing proximally dilated small bowel loops with distal collapse, suggestive of a transition point (yellow arrow) caused by an adhesive band, Case 2.

Case presentation 3

Clinical presentation

A 57-year-old Saudi male with a medical history of type 2 diabetes mellitus, hypertension, hyperlipidemia, ischemic heart disease, and obstructive sleep apnea, and a past surgical history notable for coronary artery bypass grafting (CABG) performed 4 years earlier. He visited the Emergency department complaining of a 1-day history of epigastric pain radiating to the back, worsened by movement. The pain was accompanied by multiple episodes of vomiting of food contents. There were no reported changes in bowel habits, gastrointestinal bleeding, or weight loss. On examination, the patient appeared ill and exhibited an obese body habitus. He was conscious, alert, and oriented, with stable vital signs. Abdominal examination revealed a soft, lax abdomen with localized epigastric tenderness. Laboratory investigations showed leukocytosis and elevated amylase levels.

Radiological findings

A plain CT scan of the abdomen (Fig. 4) showed mildly dilated ileal loops with internal fecalization extending to the mid-descending colon, followed by complete collapse of the remaining large bowel, including the sigmoid colon. An internal hernia was also identified, raising concern for developing obstruction.

Figure 4.

Coronal CT scan demonstrating encapsulated dilated bowel loops (yellow circle) suggestive of abdominal cocoon syndrome, Case 3.

Management and outcomes

The patient was admitted to the intensive care unit both preoperatively and postoperatively for close monitoring, given his high surgical risk based on the preoperative cardiac assessment. He underwent an exploratory laparotomy, during which a dense fibrous encapsulating membrane was identified. Surgical management included meticulous release and excision of the fibrous capsule (Fig. 5), followed by resection of the terminal ileum with primary anastomosis. As part of the etiologic workup, many peritoneal biopsies were taken during laparotomy for abdominal TB culture and negatively resulted. The patient’s recovery was gradual but steady. His gastrointestinal function returned appropriately, and his pain improved with supportive management. He was later transferred to the surgical ward and discharged once his clinical status stabilized. At his 2-week follow-up visit after discharge, he reported significant symptomatic improvement with no abdominal pain, vomiting, or bowel habit disturbances. Examination demonstrated a well-healed incision with no evidence of postoperative complications. Overall, he continued to recover well and remained clinically stable.

Figure 5.

Findings of trapped small bowel loops within a fibrous membrane, Case 3.

Discussion

EPS is an uncommon disorder that can cause varying degrees of intestinal obstruction^[1^]. Also termed abdominal cocoon syndrome, it is a chronic inflammatory disease of the peritoneum in which the serosal surface thickens and a dense fibrocollagenous membrane envelopes the intra-abdominal viscera^[1,2^]. The resulting peritoneal fibrosis creates a rigid localized sac that traps small bowel loops within tight fibrotic compartments, producing the characteristic “abdominal cocoon” appearance^[3^]. Because EPS is extremely rare and arises from diverse etiologies, its true incidence and prevalence remain uncertain^[4^]. A systematic review published in 2022 identified 240 reported cases of idiopathic EPS worldwide, with a male predominance: 151 cases (62.9%) occurred in men and 89 cases (37%) in women^[4^]. In addition to the three cases presented in this series, our review of the English-language literature found eight other EPS cases reported from Saudi Arabia between 2012 and 2024^[5–11^].

EPS is typically categorized into primary and secondary types according to whether an underlying cause can be identified^[12^]. Primary, or idiopathic, EPS occurs in the absence of a recognizable precipitating factor. In contrast, secondary EPS develops in association with specific conditions such as PD, which remains the most widely recognized risk factor. Other contributing etiologies include abdominal TB, liver cirrhosis, organ transplantation, chronic inflammatory disorders, sarcoidosis, prolonged catheter placement, and historical exposure to certain β-blockers^[13^]. Notably, none of the patients in our series had a history of PD, underscoring an atypical presentation.

In cases 1 and 3, the patients were receiving Carvedilol (a non-selective β-blocker with additional α1-blocking activity) and Bisoprolol (a selective β1-blocker), respectively, both of which are widely used contemporary agents with no established causal link to EPS^[14^]. Although β-blockers have historically been mentioned among potential contributors to secondary EPS, this association is largely limited to Practolol, a drug that was withdrawn from clinical use after being convincingly linked to severe fibrosing complications of the peritoneum^[15^]. The classic case series by Eltringham et al. demonstrated that Practolol was responsible for a distinctive form of sclerosing peritonitis characterized by dense fibrocollagenous encasement of the bowel, a finding not consistently reproduced with other β-blockers^[15^]. While early reports raised theoretical concerns regarding agents such as propranolol and oxprenolol, these observations were not substantiated by subsequent evidence and failed to establish a definitive causal relationship^[16^]. More recent comprehensive reviews emphasize that the β-blocker-associated risk of EPS has not been reconfirmed for currently prescribed agents, and Practolol remains the only β-blocker with a consistently documented etiological role in this condition^[14^]. Therefore, the use of carvedilol and bisoprolol in our patients does not provide a plausible explanation for the development of EPS, supporting the interpretation that these cases are more consistent with an idiopathic EPS (see Table 1).

Table 1.

Overview of the three clinical cases of idiopathic EPS.

Variable	Case 1	Case 2	Case 3
Age/gender	77-year-old male	37-year-old male	57-year-old male
Comorbidities	Diabetes	None	Diabetes
	Hypertension		Hypertension
	Ischemic heart disease		Prior CABG
Relevant medications	Carvedilol	None	Bisoprolol
EPS type	Primary (idiopathic)	Primary (idiopathic)	Primary (idiopathic)
Radiological findings	Dilated small bowel loops, transition zone	Trans-mesenteric internal hernia; closed-loop obstruction	Mild ileal dilation; internal hernia; large bowel collapse
Management	Exploratory laparotomy + adhesiolysis	Exploratory laparotomy + adhesiolysis + appendectomy + enterotomy closure	Exploratory laparotomy + capsule excision + terminal ileum resection + anastomosis

EPS often presents insidiously with abdominal pain and nonspecific symptoms such as anorexia, nausea, vomiting, altered bowel habits, weight loss, and malnutrition^[4,17^]. Because of their nonspecific nature, these symptoms can mimic several surgical disease entities. Internal hernia is one of the main mimickers in patients suspected of having EPS and may contribute to diagnostic confusion^[4^]. The preoperative diagnosis of EPS is challenging, as physical findings are nonspecific and no single test offers high sensitivity or specificity^[4,17^]. CT remains the most valuable imaging modality for the preoperative diagnosis. Highly suggestive CT findings include clustering or conglomeration of small bowel loops in the center of the abdomen and the presence of a thick, enhancing fibrous membrane encasing the intestines^[18,19^]. In addition, one of the distinctive radiological features is that internal hernias lack the presence of a membrane-like sac which is a typical finding in EPS^[20^]. In our case series, both patients in cases 2 and 3 were having internal hernias shown in the CT besides closed bowel loops suggestive of ESP, which happily did not delay the timely diagnosis. Despite how important the preoperative imaging in achieving the diagnosis of EPS, the gold standard diagnostic method until now is surgical exploration through laparoscopy or laparotomy, both of which serve diagnostic purposes^[4,21^].

Medical management of EPS focuses on controlling inflammation, limiting fibrotic progression, and optimizing the patient’s nutritional status. Corticosteroids remain the cornerstone of therapy in the early, inflammatory phase of the disease; they reduce peritoneal inflammation by suppressing cytokine activity, diminishing capillary permeability, and limiting the cascade of fibrin deposition that ultimately contributes to encapsulating fibrosis^[22^]. Tamoxifen, used for its anti-fibrotic and fibrinolytic effects, is generally reserved for patients whose disease has progressed to the subacute or chronic phase^[22^]. Throughout all stages, aggressive nutritional support is essential, with enteral feeding used whenever possible and total parenteral nutrition initiated when oral or enteral intake is not feasible^[23^]. This approach helps counteract the severe catabolic state associated with EPS and improves the patient’s overall suitability for surgical intervention^[23^].

Surgery becomes the definitive treatment once patients develop fixed or recurrent small-bowel obstruction, radiologic evidence of dense encapsulation “cocooning,” or medical treatment failure^[24^]. The gold standard management is an open laparotomy, which provides wide, unobstructed exposure for extensive enterolysis or adhesiolysis^[23^]. During this procedure, the surgeon carefully dissects and strips the thick fibrotic peritoneal capsule enveloping the bowel, separating densely adherent loops while preserving mesenteric blood supply^[14^]. This is a highly delicate process; the bowel is frequently edematous, distorted, and exceptionally fragile, and inadvertent enterotomies can easily occur if tactile feedback and full spatial visualization are compromised^[25^]. Open surgery therefore offers critical advantages in which the surgeon can use both hands to gently manipulate bowel loops, judge tissue tension and fragility, control small serosal tears immediately^[25^]. Although laparoscopy has been explored in selected patients, its use in EPS remains restricted. Potential benefits of laparoscopy include reduced postoperative pain, faster mobilization, and improved visualization in early or mild disease^[26^]. However, in most cases of EPS, especially when there is extensive cocooning or bowel dilation, laparoscopy carries substantial risks. Pneumoperitoneum limits tactile feedback, the working space is restricted by densely adherent loops, safe dissection planes are difficult to identify, and conversion to open surgery is often necessary^[26^]. For these reasons, laparotomy is the preferred and safest approach in most patients for precise decapsulation, and the best chance of restoring bowel function without catastrophic iatrogenic injury^[26^]. Although surgery can relieve intestinal obstruction, it does not reverse the underlying peritoneal pathology. As a result, redevelopment of fibrotic capsules and recurrence of EPS may occur in some patients, particularly within the first postoperative year^[24^].

In our case series, surgical intervention was selected as the primary management approach in all three cases due to the clear presence of mechanical small-bowel obstruction, which cannot be resolved through conservative measures once a fixed transition point is identified, as summarized in Table 1. Radiological and intraoperative findings consistently demonstrated dense adhesions and fibrous encapsulation of the small bowel, features characteristic of advanced adhesive or encapsulating pathology that necessitate operative release. Furthermore, the pattern of obstruction in the three patients, including closed-loop configurations and internal herniation, posed a substantial risk of bowel ischemia, necrosis, and potential perforation if left untreated. Collectively, these factors provided a compelling indication for early laparotomy with adhesiolysis as the safest and most definitive means of restoring bowel continuity and preventing life-threatening complications.

As the fibrotic cocoon around the bowel contracts, the disease may progress to complete obstruction with subsequent bowel ischemia and necrosis, perforation and sepsis^[27^]. The prognosis of EPS is generally poor, with reported mortality rates of approximately 26–58% after diagnosis, and up to 70%–80% in patients with severe disease^[27^]. Traditionally, there were no validated tools to predict surgical mortality in severe EPS; more recently, CT-based scoring systems have been proposed to stratify operative risk^[27^]. This case series was written in line with the process guidelines^[28^].

Limitations

This case series is subject to several limitations inherent to its retrospective design. The small sample size restricts the generalizability of the findings, and the rarity of EPS prevents broader comparative analysis. Long-term follow-up was not available for all patients, limiting assessment of recurrence and late complications. Imaging interpretation and surgical decision-making were also case dependent and may not reflect practices across different centers. Despite these constraints, the series provides valuable clinical insights into the diagnostic challenges and surgical management of this uncommon condition.

Conclusion

EPS remains an exceptionally rare and diagnostically challenging condition whose clinical presentation often masquerades as more common surgical emergencies. Our three cases illustrate how subtle symptoms, nonspecific laboratory findings, and overlapping radiologic features can easily obscure the diagnosis, emphasizing the need for heightened suspicion. Despite advances in imaging, operative exploration continues to be both the definitive diagnostic tool, and the cornerstone of effective management once fixed obstruction or dense fibrotic cocooning has occurred. Laparotomy with adhesiolysis and decapsulation offers the most reliable means of relieving obstruction and preventing catastrophic complications. Although postoperative recurrence may occur due to persistent peritoneal fibrosis, early surgical intervention remains the most effective strategy for restoring gastrointestinal continuity and improving patient outcomes. These cases reinforce the importance of recognizing EPS even in patients without conventional risk factors and highlight the critical role of timely surgical management in mitigating morbidity associated with this rare but potentially devastating condition.

Ethical approval

Our submission is a case series that involves a limited number of patients, and it does not involve any new interventions or prospective data collection for research purposes. As such, it falls outside the scope of what is typically considered “systematic research” that would require IRB approval. All patients’ written consent was obtained with approval of Prince Saud bin Jalawi Hospital and King Fahad Hospital Alhufuf.

Consent

Written informed consent was obtained from the patients for publication of this case series and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Sources of funding

Not applicable.

Author contributions

F.A.M.: Conceptualization, Writing – original draft, and Visualization. B.A.M.: Resources, Investigation, and Data curation. S.A.S.: Resources, Investigation, and Data curation. E.A.: Resources and Project administration. A.A.A.: Writing – review and editing. M.A.: Validation and Supervision.

Conflicts of interest disclosure

Not applicable.

Research registration unique identifying number (UIN)

1. Name of the registry: research registry. 2. Unique identifying number or registration ID: 11420. 3. Hyperlink to your specific registration (must be publicly accessible and will be checked): here: https://www.researchregistry.com/browse-the-registry/#home/registrationdetails/688ce8ce19a50102c3ae530d/ .

Guarantor

Dr. Fatimah Al Mazrou and Dr. Eman Almaher.

Provenance and peer review

Not commissioned; externally peer reviewed.

Data availability statement

Data sharing is not applicable to this article as no datasets were generated or analyzed for this case series

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work, the authors used Chat Open AI in order to check the manuscript for grammatical mistakes and improve readability and language. After using this tool/service, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.