A Case Series and Brief Review of Literature on Encapsulating Peritoneal Sclerosis: Unveiling the Cocoon.

This case series demonstrates the diverse presentations and outcomes of encapsulating peritoneal sclerosis (EPS) in patients with varying underlying conditions, including post-liver transplant complications, abdominal tuberculosis, congenital syndromic anomalies, and disseminated infections. EPS diagnosis was confirmed through characteristic imaging findings, such as encapsulated ascites, clumped bowel loops, and unique appearances (e.g., "cauliflower" and "concertina-like") observed on contrast-enhanced computed tomography (CECT) and USG. Table 1 demonstrates a summary of four cases, illustrating the varying presentations, imaging features, diagnoses, and outcomes of encapsulating peritoneal sclerosis (EPS) across diverse underlying conditions. LDLT: living donor liver transplant, CHARGE: coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and development, genital abnormalities, and ear anomalies, including deafness, CT: computed tomography, CECT: contrast-enhanced computed tomography, EPS: encapsulating peritoneal sclerosis, USG: ultrasound, XDR: extensive drug-resistant, TB: tuberculosis, MTB:  Mycobacterium tuberculosis , RIF: rifampicin. MODS: multiple organ dysfunction syndrome, ATT: antitubercular therapy Case 1 A 41-year-old male patient with coronary artery disease and type 2 diabetes mellitus, status post-living donor liver transplant (LDLT), and known portal vein thrombosis on oral anticoagulants presented with generalized body pain, abdominal distension, occasional breathing difficulty, and pedal edema for one week. Initial abdominal ultrasound (USG) revealed a thrombus in the portal vein extending to its anterior and posterior branches, as well as middle hepatic vein thrombosis. Portal stenting was performed (Figure 1d ). The two-month follow-up ultrasound showed ascites, clumped bowel loops with a trilaminar appearance of a hyperechoic membrane, hypoechoic bowel wall, and hyperechoic bowel lumen/mucosa-probable features of peritoneal encapsulation. Imaging suggested features of encapsulating peritoneal sclerosis (Figure 1a - 1c ). CT: computed tomography, CECT: contrast-enhanced computed tomography, GS: greater sac, LS: lesser sac, EPS: encapsulating peritoneal sclerosis The patient was planned for immediate laparotomy and adhesion lysis to relieve peritoneal visceral constriction. Bronchoalveolar lavage (BAL) culture revealed Stenotrophomonas maltophilia , with a colony count of >100,000 colony-forming unit (cfu)/mL. The patient succumbed to extensive drug-resistant (XDR) sepsis and multiple organ dysfunction syndrome (MODS). Case 2 A 31-year-old male patient presented with abdominal distension and weight loss. Ultrasound (USG) findings indicated encapsulating peritoneal sclerosis (EPS), with ascites and clumped small bowel loops (Figure 2a , 2b ). Subsequent contrast-enhanced CT (CECT) confirmed encapsulated ascites and clumped small bowel loops (Figure 3 ). CT: computed tomography, TB: tuberculosis Diagnostic laparoscopy and peritoneal/omental biopsy were done, and omental sample histopathology showed a necrotizing (caseating) granulomatous lesion, suggestive of tuberculosis. The acid-fast bacteria (AFB) stain was negative. His GeneXpert  Mycobacterium tuberculosis (MTB)-rifampicin (RIF) test (peritoneal tissue) revealed a  Mycobacterium tuberculosis complex. Antitubercular therapy (ATT) was started, and the patient symptomatically improved and was discharged with advice to be on regular follow-up. Case 3 A 26-day-old female term neonate with acyanotic congenital heart disease (CHD), type B aortic arch interruption, an aberrant right subclavian artery from the descending thoracic aorta, and small perimembranous ventricular septal defect (VSD) closed by the tricuspid septal leaflet presented with syndromic features possibly indicative of CHARGE syndrome. Findings included right iris coloboma, right corneal opacity, left choanal atresia, facial dysmorphism, and rocker-bottom feet. The neonate developed respiratory distress and desaturation shortly after birth, with notable umbilical cord swelling. Initial abdominal USG and X-ray showed no evidence of perforation or peritonitis, but repeat USG indicated features of bowel obstruction. Contrast-enhanced CT revealed loculated fluid collections in the greater and lesser sacs with enhancing peritoneal covering and small air pockets along the anterior aspect of these collections. Small bowel loops were clumped toward the root of the mesentery without definite dilation, while large bowel loops were collapsed, suggestive of perforation with encapsulated peritonitis. Imaging also showed heterogeneous liver enhancement and communication between the portal vein and inferior vena cava (IVC), likely representing Abernethy malformation (Figure  4 ). The neonate subsequently experienced cardiopulmonary arrest secondary to septic shock and succumbed. CT: computed tomography, GS: greater sac, LS: lesser sac Case 4 A 41-year-old male patient with diabetes and hypertension presented with a three-week history of fever, two-week history of cough, and one-month history of weight loss (3-4 kg over four months). He was diagnosed with disseminated tuberculosis (TB). Physical examination revealed pallor, abdominal distension, and shifting dullness. Abdominal USG showed liver with altered echotexture, surface irregularities, multiple cysts, and hypoechoic lesions, along with moderate ascites with septations. Small bowel loops were stacked at the root of the mesentery (Figure 5a , 5b ). CT of the chest demonstrated endobronchial infection with nodules and peribronchovascular nodular consolidations (Figure 5d , 5e ). HRCT: high-resolution computed tomography, CT: computed tomography Abdominal CT revealed probable peritoneal TB with enhancing peritoneal covering, encapsulating peritoneal sclerosis, multiple hypodense hepatic and splenic lesions, omental caking, and multiple enlarged and necrotic abdominal and mediastinal lymph nodes, suggestive of granulomatous infection (Figure 6a - 6d ). Overall imaging features suggested wet-type abdominal tuberculosis. CT: computed tomography Diagnostic tapping of ascitic fluid revealed low serum-ascites albumin gradient (SAAG), high protein ascites, and elevated adenosine deaminase (ADA) level (92 U/L), suggestive of TB. Ascitic fluid cytopathology showed no atypical or malignant cells, and the fluid culture was negative. Ascitic fluid GeneXpert analysis showed trace positivity. Sputum samples tested negative for Gram staining, AFB, and fungal smear. However, culture revealed Enterobacteriaceae, and antibiotics were continued. Endobronchial ultrasound (EBUS)-guided BAL samples detected Mycobacterium tuberculosis , and cytopathology revealed granulomatous lymphadenitis with necrosis. The patient was started on an ATT regimen and showed symptomatic improvement.

Encapsulating peritoneal sclerosis (EPS), otherwise known as abdominal cocoon, is an inflammatory disease of the peritoneum, characterized by the encapsulation of the abdominal viscera and intestines within a thickened fibrocollagenous membrane [ 1 ]. Early detection is crucial for preventing severe complications such as recurrent bowel obstruction, adhesions, perforation, and sepsis, improving prognosis, and expanding treatment options. EPS frequently occurs in patients undergoing peritoneal dialysis for end-stage renal disease [ 2 ]. Chronic exposure to dialysate solution during peritoneal dialysis can lead to peritoneal inflammation and scarring, which may progress to peritoneal sclerosis. EPS can also develop following various surgeries and organ transplantations, including liver transplantation, due to trauma and inflammation. The etiology can be a wide spectrum [ 3 - 22 ]. In developing countries, tuberculosis is a common infectious cause; other infectious etiologies include intraperitoneal infections, particularly from Staphylococcus aureus , Pseudomonas , and various fungal species, which can significantly contribute to the development of EPS, especially in immunocompromised patients. Diagnostic imaging, particularly ultrasound (USG) and computed tomography (CT), plays a critical role in the early identification of EPS. Peritoneal Abnormalities The inflammatory process affects the peritoneum diffusely, resulting in widespread peritoneal fibrosis. This manifests as peritoneal thickening, which can be smooth or irregular and nodular. Small Bowel Abnormalities The sclerosed, thickened peritoneum surrounds the small bowel loops, leading to bowel obstruction. Varying lengths of small bowel may be tightly enclosed within pockets of fibrotic peritoneum, described as an "abdominal cocoon." In this case series, we present a comprehensive analysis of four distinct cases of encapsulating peritoneal sclerosis (EPS). Our aim is to illustrate the varied clinical presentations and outcomes of EPS to enhance understanding and aid in diagnosis and early detection. After completing this journal activity, participants will be able to examine the terminology and underlying causes of encapsulating peritoneal sclerosis (EPS), identify the multimodality imaging appearances and complications of EPS, and discuss the differential considerations and management of EPS.

Encapsulating peritoneal sclerosis (EPS) is a rare yet significant condition marked by high morbidity and potential mortality. Diagnosing EPS is challenging due to its gradual onset and nonspecific symptoms, which often contribute to diagnostic delays. Radiologic imaging, however, can play an essential role in the early identification of EPS, with timely intervention and potentially improving patient outcomes. Table 2 presents various etiologies for encapsulating peritoneal sclerosis (EPS), highlighting the different underlying conditions that can lead to its development. EPS: encapsulating peritoneal sclerosis Differential diagnosis Several conditions fall within the differential diagnosis of EPS, including congenital peritoneal encapsulation, peritoneal carcinomatosis, and internal hernias. Congenital peritoneal encapsulation is a benign condition characterized by a thin accessory peritoneal membrane surrounding the small bowel, typically asymptomatic and usually discovered incidentally during surgery or radiologic examinations. Peritoneal carcinomatosis, on the other hand, is identified by thickening and abnormal enhancement of the peritoneum. It can be differentiated by its nodular thickening pattern and associated findings such as nodules in the omentum, pouch of Douglas, and serosal surfaces, often accompanied by lymphadenopathy and primary tumors such as ovarian or gastric cancers. Internal hernias may also resemble EPS due to the abnormal clustering of bowel loops, but they lack the characteristic soft-tissue mantle of EPS. Additionally, internal hernias tend to occur in fixed anatomical regions and carry a higher risk of bowel ischemia from compromised vascular pedicles [ 21 ]. Complications EPS can lead to severe and sometimes life-threatening complications, significantly impacting patients' quality of life. Bowel obstruction is one of the primary complications, as fibrocollagenous encapsulation of the bowel leads to sclerosis and membrane contraction, mechanically obstructing the bowel. Malnutrition is another significant risk, as recurrent bowel obstructions hinder adequate nutrient absorption. Bowel ischemia and infarction may occur as well, with fibrotic encapsulation compressing bowel loops and compromising the blood supply, potentially leading to ischemia and necrosis. Increased pressure on and weakened integrity of the bowel wall can also result in perforation and subsequent peritonitis, with recurrent infections heightening the risk of systemic sepsis. Other complications of EPS include extensive adhesions and fistulas between bowel segments or adjacent organs as a result of chronic inflammation and fibrosis. Ascites in EPS patients can further cause respiratory compromise, often necessitating repeated drainage procedures. The fluid imbalance also places patients at risk of electrolyte disturbances and renal dysfunction due to reduced absorption. Ultimately, EPS is associated with an increased mortality rate, particularly in cases with delayed diagnosis and treatment, underscoring the critical role of radiology in early detection and management. Advanced imaging techniques, including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), are invaluable in identifying hallmark features of EPS such as bowel encapsulation, ascites, peritoneal thickening, and the characteristic clumping of bowel loops. Early radiologic identification of these signs allows for timely intervention, which can significantly impact prognosis and reduce the risk of severe complications. Radiology, therefore, plays a pivotal role in guiding clinical decision-making and improving outcomes for patients with EPS through enhanced accuracy and precision in diagnosis.

Encapsulating peritoneal sclerosis (EPS) is a rare but serious condition often underdiagnosed due to limited awareness among healthcare providers, despite being a leading cause of small bowel obstruction in tertiary care hospitals. Early diagnosis, supported by multimodal imaging such as contrast-enhanced CT (CECT) and ultrasound, is essential for detecting key features and improving patient outcomes. The condition's multifactorial etiology requires individualized treatment plans tailored to the underlying cause. A collaborative effort among clinicians, radiologists, and researchers is critical to enhance awareness, refine diagnostic approaches, and optimize treatment strategies for EPS. Future research should focus on establishing standardized protocols to improve care and outcomes for patients with this challenging condition.