Clinical features of abdominal cocoonism, CT diagnosis

Abdominal cocoonism is a rare, unexplained peritoneal disease, first reported and named by Foo in 1978, characterized by all or part of the small intestine is surrounded by a layer of grayish-white, tough and hard fibrous membrane, shaped like a "silkworm cocoon", also known as idiopathic sclerosis peritonitis, small bowel confinement, small intestinal fibrous membrane wrapping and so on

There are no specific clinical symptoms and laboratory diagnostic indicators of this disease, often with abdominal mass or incomplete intestinal obstruction as the first symptom, preoperative diagnosis is difficult, mostly found during laparotomy, but the lesion is progressive, and the consequences of delayed diagnosis and treatment are serious

Clinical features

Abdominal calluses are clinically rare, and the exact cause is unclear so far, and may be related

Another category of relatively clear etiologies is classified as secondary abdominal cocoonism, including tuberculous peritonitis, non-specific abdominal inflammation, long-term peritoneal dialysis, cirrhosis abdominal effusion in patients with abdominal vena cava transfusion, intra-abdominal chemotherapy, and liver transplantation, etc.

Abdominal cocoonism is clinically divided into localized and diffuse types, the former refers to part of the small intestine or organs wrapped in fibrous membranes, and the latter refers to all small intestines with or without other organ wrapping

Often without specific clinical manifestations, there may be abdominal mass, abdominal pain, bloating, vomiting and other symptoms of acute or chronic intestinal obstruction; The abdomen is asymmetrical and can touch a whole, smooth, non-shrinking mass

Intestinal obstruction caused by abdominal cocoonism is mainly due to local irregular thickening of the fibrous membrane and compression of the intestinal canal; Surgery is the main treatment of membrane cocoonism, as completely as possible to remove the fibrous membrane wrapped in the small intestine, loosen adhesions, partially perform intestinal alignment at the same time, pay attention to intestinal dysfunction and correct electrolyte imbalance after surgery, and encourage patients to get out of bed early

Female, 39 years old, repeated abdominal pain, bloating for 5 years, and then aggravated for another day

Diffuse abdominal cocoonism: X-ray standing abdominal flat film showing local expansion of the small intestine with multiple fluid-air levels of varying sizes; CT panning shows that the thickened membrane in the abdominal cavity (short arrow) envelops all small intestines to form a well-defined clumpy structure, the membrane is about 1-2mm thick, its intestinal tract is dilated, detoured, fixed, and gathered, the intestinal wall is thickened, and the fat gap between the intestines is blurred (long arrow).

Male, 50 years old, recurrent abdominal pain and bloating, 2 years, recurrence of exacerbations with nausea and vomiting for 3 months

Diffuse abdominal cocoonism: thickened, significantly strengthened membranes in the abdominal cavity envelop all large and small intestines and abdominal organs to form a well-defined clumpy structure, and membranes (short arrows) and intestinal changes (see intestinal obstruction, fixation, convergence) (long arrows) are progressively aggravated, and local peritoneal thickening adhesions are progressive

Membrane pathology: fibroconnective tissue hyperplasia with necrosis, hyperemia, and more inflammatory cell infiltration (HE×200)

Imaging presentation

Plain x-ray of the abdomen standing upright:

Manifested as signs of intestinal obstruction but not specific;

Barium contrast of the small intestine:

Male, 38 years old; Recurrent abdominal pain and bloating for 3 years, worsening for 5 months

Diffuse abdominal cocoonism: the large and small intestines in the abdominal cavity and around the abdominal organs are wrapped in significantly strengthened and thickened membranes (short arrows), the intestinal tubes are fixed and gathered into a lumpy structure, the intestinal wall is thickened (long arrows), and the local peritoneal thickening adhesions are seen; Barium in the upper gastrointestinal tract shows that the left upper quadrant jejunum is fixed, gathered, and folded and arranged into a "twist twist" shape, which is not easy to separate after fixation and pressure, and the barium agent is obviously delayed; Figures E and F show that the abdominal endometrial substance (short arrow) is thickened and blurred compared with the front, the signs of enclosed small intestinal obstruction are more obvious, the intestinal dilation and intestinal wall thickening and blurring with interintestinal and abdominal effusion (long arrows), and the interintestinal fat gap is blurred, showing progressive aggravation

Male, 49 years old, repeated abdominal pain, bloating for 1 month, stop defecation for 1 day

Localized abdominal cocoonism: thickened, significantly strengthened membranes in the abdominal cavity (short arrows) wrap around the small intestine to form a lumpy structure, the small intestine in the membrane is twisted, expanded, fixed, gathered and adhered (long arrows), and local peritoneal thickening; During the operation, the abdominal cavity and intestinal canal were not seen after the opening of the abdomen, and the small intestine was covered with a layer of milky white, transparent and tough cellulose film, and the surface of the membrane was smooth and the thickness was about 2mm; Membrane pathology: hyperplasia of fibrogranuloma tissue with vitreous degeneration and focal hemorrhage (HE×200

Male, 42 years old, repeated abdominal pain, bloating for 1 year, aggravated by 2 months

Diffuse abdominal cocoonism: significantly strengthened and thickened membranes (short arrows) are seen around the large and small intestines of the abdominal cavity, the intestinal tubes in the membrane converge into a lumpy structure, some intestinal dilations and effusions, thickening of the intestinal wall, and local thickening of the peritoneum; CTA of the abdomen shows that the blood supply arteries of the intestine are twisted and aggregated, and the blood vessels travel unnaturally
.

Left: Female, 17 years old, abdominal pain 2 months
after appendectomy.

Localized abdominal cocoonism: abnormally thickened membranes (short arrows) in the right, middle and lower abdominal cavities, wrapping the local intestinal tube into a clumpy structure, and local intestinal fixation! Convergence and interintestinal adhesions, local peritoneal thickening; The other right anterior abdominal wall is shown for postoperative changes
.

Right: Female, 53 years old, after total gastrectomy of gastric cancer, 4 months, nausea, vomiting for more than
2 months.
Diffuse abdominal cocoonism: abnormal thickening of the intraperitoneal membrane ( short arrow) envelops the intestines and fluids into a clumpy structure, the membrane thickness is uneven, the local peritoneum is thickened, and the local intestine is fixed! Convergence and obvious adhesions between the intestines and the anterior abdominal wall; The left bowel and anterior abdominal wall are postoperatively altered
.

differential diagnosis

It needs to be distinguished from the following diseases causing intestinal obstruction:

Sclerosing peritonitis: more often occurs in patients after long-term peritoneal dialysis or multiple abdominal chemotherapy, physical examination of the abdominal wall is tight and the texture is tough as a plate, CT can show peritoneal thickening and extensive adhesion with abdominal organs, signs of intestinal obstruction are relatively light, no cocoon-like fibrous envelope; The strong adhesions between the intestinal tubes are difficult to be separated and removed surgically, and are generally non-surgical
treatment.

Adhesion intestinal obstruction: mostly secondary to postoperative or abdominal tuberculosis, clinical recurrent incomplete intestinal obstruction, clinical identification is difficult, but the site of the obstruction on CT presents with local intestinal disorders, local obvious adhesion formation, no signs of intestinal wrapping, and the etiology is relatively clear
.
Abdominal cocoons are prone to adhesion intestinal obstruction, and the display of cocoon-like fibrous envelopes is helpful in the diagnosis
of abdominal cocoonism.

Bowel voltaic and intra-abdominal hernia: loop occlusion and adjunctive mesangial vascular aggregation, traction, distortion, and mass signs help diagnose both, and the display of hernia can confirm the diagnosis of intra-abdominal hernia, and the clinical condition is relatively urgent and severe, lacking obvious repetition; Neither has a cocoon-like fiber envelope on CT
.

Peritoneal envelopsis: it is a rare congenital anomaly, the peritoneum of the development is similar to normal, the peritoneum wraps the small intestine to form an intra-abdominal hernia, the inner wall of the envelope is smooth, there is no adhesion to the small intestine, the intestinal peristalsis is generally unrestricted, and intestinal obstruction
occurs less.

in a word