DOI:10.2214/AJR.05.0252
AJR 2006; 186:905-906
© American Roentgen Ray Society
MRI Findings in Intestinal Cocoon
Lina Menassa-Moussa,
Leila Bleibel,
Claude Sader-Ghorra,
Tarek Smayra and
Noël J. Aoun
Hôtel Dieu de France Beirut, Lebanon
Abdominal cocoon is a well-known but rare cause of small-bowel obstruction
in which all or part of the small bowel is encased by a fibrous capsule,
giving the appearance of a cocoon. Approximately 70 cases have been reported
in the literature. The diagnosis is rarely made preoperatively. To our
knowledge, MRI features have never been reported.
A 40-year-old man was hospitalized for lower abdominal pain, nausea,
vomiting, and abdominal distention occurring intermittently over the past 5
years and increasing in frequency. Abdominal sonography, colonoscopy, and
gastroscopy were normal. Blood analyses were unremarkable.
A barium meal and follow through revealed a dilated jejunum proximal to
ileal loops that were agglomerated in a concertina-like fashion
(Fig. 2A). The colon was normal
and the distal ileal loop was identified. CT revealed a diffuse dilatation of
the small-bowel loops proximal to the jejunoileal junction. Ileal loops were
also dilated and agglomerated in a concertina-like fashion; a linear dense
structure was seen encircling the bowel loops
(Fig. 2B).
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Fig. 2A —40-year-old man with abdominal cocoon. Small-bowel follow-through
barium examination shows ileal loops agglomerated in concertina-like fashion
with sacculated appearance mimicking normal colon (asterisk).
Transverse colon is well seen, containing air (oblique arrow).
Horizontal arrow points to jejunal loops.
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Fig. 2B —40-year-old man with abdominal cocoon. CT scan shows sacculated
ileal loops (arrow) anterior to dense linear structure
(arrowheads) probably corresponding to fibrous membrane found at
surgery.
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Because we were not aware of this disease and for further evaluation of the
peritoneal space and small-bowel wall, MRI was performed on a 1.5-T Signa
Infinity (GE Healthcare). The linear dense structure was also visualized on
MRI (Fig. 2C), and a coronal
section (Fig. 2D) revealed the
same pattern as the barium study. At laparotomy, the proximal bowel loops were
dilated but normal; the distal loops were encapsulated in a whitish, thick
membrane. After this capsule was incised, the bowel loops were easily freed
and had a normal appearance. On histologic examination, the membrane was found
to be composed of fibrous tissue with mononuclear inflammatory cells.
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Fig. 2C —40-year-old man with abdominal cocoon. Axial single-shot spin-echo
T2-weighted image (TR/TE, 6,800/99.4) shows sacculated, dilated bowel loops
(arrow) and fibrous membrane (arrowheads) seen on CT.
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Fig. 2D —40-year-old man with abdominal cocoon. Coronal single-shot spin-echo
T2-weighted image (2,195.9/88.1) shows sacculated bowel loops
(arrowheads) and normally positioned transverse colon
(arrow) in disposition comparable to that of barium study.
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This entity was first described in perimenarchal girls of the tropics and
subtropics and was thought to be caused by viral peritonitis complicating
retrograde menstruation [1]. It
was also reported in patients receiving oral practolol (ß-adrenergic
blocker), in cirrhotic patients treated by peritoneovenous shunt, in patients
on chronic ambulatory peritoneal dialysis, and after orthotopic liver
transplantation. In cases such as ours, it is idiopathic.
On barium studies, a cauliflower appearance or concertina-like pattern seen
in our case has been reported by several authors
[2]. It corresponds to the
clustering of otherwise normal small-bowel loops. This finding was also
evident on the coronal MRI section. CT was performed in a few cases. CT not
only displays crowding of the small-bowel loops just as the barium study does,
but it may also show the soft-tissue capsule encircling the bowel loops
[2-4].
These findings were also seen on MRI.
In conclusion, except for anecdotal reports, the majority of cases of
sclerosing peritonitis are still diagnosed at surgery. On barium studies, this
entity must be suspected when a concertina-like or cauliflower pattern is
seen. On CT, a fibrous capsule encircling the bowel loops is highly
suggestive. MRI can display both findings. More thorough knowledge by
radiologists of these findings on barium studies; CT; and, now, MRI must
result in more frequent preoperative diagnoses based on one or two of these
techniques.
References
- Foo KT, Ng KC, Rauff A, Foong WC, Sinniah R. Unusual small
intestinal obstruction in adolescent girls: the abdominal cocoon.
Br J Surg 1978;65
: 427-430[Medline]
- Lalloo S, Krishna D, Maharajh J. Case report: abdominal cocoon
associated with tuberculous pelvic inflammatory disease. Br J
Radiol 2002; 75:174
-176[Abstract/Free Full Text]
- Wig JD, Gupta SK. CT in abdominal cocoon. J Clin
Gastroenterol 1998; 27:259
-260[CrossRef][Medline]
- Gupta S, Shirahatti RG, Anand J. CT findings of an abdominal
cocoon. AJR 2004;183
: 1658-1660[Free Full Text]
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