Rare Abdominal Cocoon Syndrome Wraps the Bowel in a Fibrous Shell, Surgeons Report

Surgeons in Tunisia have described a strikingly rare condition in which the small intestine becomes wrapped inside a dense, whitish fibrous membrane, resembling a cocoon, in a case report published in the open-access journal Heliyon. The 58-year-old patient arrived at the emergency department after three months of recurring abdominal pain, bloating, nausea, and intermittent vomiting, and the surgical team ultimately diagnosed abdominal cocoon syndrome, also known as idiopathic sclerosing encapsulating peritonitis. The report, authored by Imen Ben Ismail, Marwen Sghaier, and colleagues, pairs the detailed clinical narrative with a review of nearly two decades of published cases, offering one of the most consolidated recent pictures of a disease so uncommon that fewer than 300 cases have been reported worldwide.

Abdominal cocoon syndrome is a condition in which a fibrocollagenous membrane gradually encases loops of the small bowel, constricting them into a clustered mass that behaves like a mechanical bottleneck for digestion. The result is recurrent or complete small bowel obstruction, one of the most common surgical emergencies encountered worldwide. Obstruction of the small intestine is usually caused by postoperative adhesions, hernias, malignancy, or inflammatory bowel disease, but cocoon syndrome stands apart because it can strike patients who have never had abdominal surgery, a detail that makes clinicians far less likely to suspect it. The syndrome was first described in the medical literature in 1978, and its etiology remains poorly understood, though an inflammatory cascade is thought to stimulate fibroblast proliferation and collagen deposition, eventually producing the dense encapsulating layer that gives the disease its name.

The Tunisian patient’s history was notable precisely for its emptiness. He denied any prior abdominal surgery, peritoneal dialysis, abdominal trauma, appendicitis, gastrointestinal perforation, foreign-body ingestion, peptic ulcer disease, or inflammatory bowel disease. He took no chronic medications, including corticosteroids, nonsteroidal anti-inflammatory drugs, or opioids, and had no diabetes, hypertension, or autoimmune disorders. His family history was unremarkable for gastrointestinal disease or tuberculosis. On admission he appeared mildly dehydrated, with a distended, tympanic abdomen and diffuse tenderness but no signs of peritonitis. Laboratory tests showed mild leukocytosis of 13,000 cells per cubic millimeter, with otherwise normal electrolytes and inflammatory markers. Abdominal radiography revealed multiple air-fluid levels consistent with partial small bowel obstruction, prompting further imaging.

Contrast-enhanced computed tomography proved decisive. The scan demonstrated hydro-aeric distension of intestinal loops up to 57 millimeters in diameter, with progressive tapering in the right iliac fossa and moderate free fluid in the pelvis and left paracolic gutter. The characteristic finding, described in the literature as the cauliflower or cocoon sign, is a cluster of small bowel loops surrounded by a fibrotic sac, and the authors note that contrast-enhanced CT is considered the imaging modality of choice because of its ability to demonstrate this pattern. Even so, the diagnosis can remain elusive. Many cases in the published literature, including several in the review accompanying this report, were confirmed only during surgery, because the radiologic features are nonspecific and the syndrome itself is so rare that few radiologists or surgeons encounter it more than once in a career.

The patient was initially managed conservatively with nasogastric decompression, fluid resuscitation, and correction of electrolyte imbalance, a standard first-line approach for partial bowel obstruction. But his obstructive symptoms persisted after 48 hours, and the surgical team decided that exploratory laparotomy was indicated. Inside the abdomen, they found the small intestine encased within a dense, whitish fibrous membrane forming a cocoon-like sac. There was no mesenteric lymphadenopathy, no caseous nodules, and no purulent fluid, findings that helped argue against an infectious cause. The surgeons performed careful adhesiolysis, the deliberate freeing of adhesions, and total excision of the fibrotic capsule without bowel resection, because all loops were viable and regained peristalsis after release. Peritoneal fluid and membrane biopsies were sent for microbiological and histopathological evaluation, including acid-fast bacillus staining, culture, and adenosine deaminase assay, all of which came back negative for tuberculosis.

That tuberculosis work-up was not a formality. Secondary forms of abdominal cocoon syndrome are associated with peritoneal dialysis, tuberculosis, autoimmune diseases, and chronic infections, and the authors emphasize that clinicians evaluating recurrent small bowel obstruction should actively exclude tuberculous peritonitis, which can closely mimic the idiopathic form. They recommend a detailed tuberculosis history, chest imaging, and, when suspicion exists, targeted investigations such as ascitic or peritoneal fluid acid-fast bacillus smear, adenosine deaminase assay, culture, and molecular testing with CB-NAAT or GeneXpert. During surgery, representative peritoneal biopsy and fluid sampling for histopathology and microbiology are strongly recommended, because macroscopic appearance alone may not reliably exclude tuberculosis. In this case, histopathologic examination confirmed fibrocollagenous tissue without granulomatous inflammation, supporting an idiopathic diagnosis.

The postoperative course was swift. The patient was monitored for the return of bowel function, abdominal distension, and signs of infection, and oral intake resumed on postoperative day two after the passage of flatus. He received prophylactic antibiotics, ceftriaxone combined with metronidazole for 48 hours, along with analgesia, and was discharged on postoperative day four with normal bowel transit. At follow-up visits at two and six weeks he remained asymptomatic, and he expressed satisfaction with the outcome while providing written consent for publication of his clinical details and images. The authors report that early operative management of this syndrome generally results in excellent postoperative recovery and minimal recurrence, and their patient’s trajectory illustrates that point in practice.

To place the case in context, the team reviewed English-language literature on abdominal cocoon syndrome published between January 2015 and June 2024, searching PubMed and Google Scholar and including only single case reports and small case series with sufficient clinical detail. The synthesis, spanning cases from Pakistan, the United Kingdom, China, Greece, Egypt, Saudi Arabia, Iraq, Turkey, Kuwait, Morocco, India, Thailand, and Ethiopia, highlights that the syndrome predominantly affects young to middle-aged males from tropical and subtropical regions. Yet the collected cases also show the disease’s range of severity: some patients presented with straightforward obstruction, while others arrived with bowel perforation, internal fistulas, ischemic segments, or extensive small bowel necrosis. In a Thai series of three patients, one died, underscoring that delays in diagnosis can carry fatal consequences. Notably, the review also documents that idiopathic forms in middle-aged and older adults, like the Tunisian patient, are increasingly reported, even though the classic textbook portrait involves younger men.

Treatment remains an area of active debate. In early stages or in cases with intermittent symptoms, conservative management with bowel rest, hydration, nutritional support, and nasogastric decompression may be attempted. But when obstruction is complete or conservative measures fail, surgery is mandated, and the definitive procedure involves adhesiolysis and careful removal of the fibrous membrane encasing the intestine. There is growing interest in laparoscopic approaches, which offer reduced postoperative pain, faster recovery, and shorter hospital stays, and one case in the review achieved an excellent outcome with laparoscopic adhesiolysis. However, minimally invasive management is technically challenging because of dense adhesions and the risk of bowel injury, so case selection is crucial and conversion to open surgery may be required if safe dissection cannot be ensured. In the present case, the authors considered laparoscopy but deferred it because marked intestinal distension and dense adhesions on imaging made open laparotomy the safer approach. In patients with advanced liver cirrhosis or other comorbid conditions, perioperative morbidity is significantly heightened and approaches must be tailored accordingly.

The authors acknowledge the limits of the evidence base. No definitive pathophysiologic mechanism or molecular biomarker exists to distinguish idiopathic from secondary forms before surgery, CT sensitivity for early or partial disease is limited, and because the condition is so rare, treatment algorithms are largely derived from isolated case reports rather than comparative studies. Recurrence is exceptional but may occur when fibrotic tissue excision is incomplete or persistent inflammation promotes re-encapsulation, so the team advises structured follow-up with clinical evaluation at three and twelve months and abdominal imaging if symptoms return. Medical therapies aimed at modulating peritoneal fibrosis, including short courses of corticosteroids or tamoxifen, have been reported anecdotally but require validation, and the authors call for future multicenter registries to define optimal surveillance intervals and identify predictive factors for recurrence. Their central message for clinicians is straightforward: abdominal cocoon syndrome deserves a place on the differential diagnosis for any patient with recurrent or unexplained small bowel obstruction, especially those who have never undergone abdominal surgery, because timely recognition, careful bowel-preserving membrane excision, and structured postoperative monitoring can convert a potentially dangerous condition into one with an excellent outcome.

Subject of Research: Abdominal cocoon syndrome as a rare cause of small bowel obstruction

Article Title: Small bowel obstruction secondary to abdominal cocoon syndrome: Case report and review of the literature

Article References: Ben Ismail, I., Sghaier, M., Amari, R., Yaakoubi, J., Zenaidi, H., & Zoghlami, A. (2026). Small bowel obstruction secondary to abdominal cocoon syndrome: Case report and review of the literature. Heliyon, 12(15), Article e45437. https://doi.org/10.1016/j.heliyon.2026.e45437

Image Credits: AI Generated

DOI: 10.1016/j.heliyon.2026.e45437

Keywords: abdominal cocoon syndrome, sclerosing encapsulating peritonitis, small bowel obstruction, case report, computed tomography, adhesiolysis, fibrous membrane, tuberculosis, general surgery, Heliyon, idiopathic peritoneal sclerosis, laparotomy