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Abstract
To the Editor: Mesocolic hernias are rare congenital abnormalities caused by malrotation
of the midgut and entrapment of the major part of the small gut within a peritoneal
sac formed by the developing mesentry of the descending colon.1 They present with
chronic digestive symptoms or with acute intestinal obstruction, gangrene or perforation
of the gut.2 They are mostly diagnosed incidentally at laparotomy for other conditions
or at autopsy.3
We describe an adult male with left-sided mesocolic hernia, presenting with chronic
atypical abdominal pain and dyspeptic symptoms along with a very unusual finding of
a fairly large and extremely mobile abdominal lump. A 40-year-old man presented with
acute colicky abdominal pain along with bilious vomiting for 12 hours and a history
of episodic abdominal pain and dyspepsia since childhood. For the last 3 months he
could feel a lump in the left upper abdomen, mostly during the episodes of pain. Physical
findings included an extremely mobile, globular, slightly tender mass about 10 cm
in diameter, in the left upper quadrant (LUQ) of the abdomen. Total blood count and
biochemical parameters were normal. Straight x-ray of the abdomen showed dilated loops
of small gut in the LUQ. An upper GI barium study, done after conservative management
and which relieved his obstructive symptoms, revealed conglomerated loops of small
gut in the LUQ of the abdomen, a caecum at a higher level than normal and to the left
of midline (Figure 1). Exploration revealed almost ⅔ of the small gut encapsulated
in the LUQ within a peritoneal sac formed by the descending mesocolon, after gaining
entry through a ring below the fourth part of the duodenum. An engorged inferior mesenteric
vein (IMV) formed the anterior border of the neck of the sac while the inferior mesenteric
artery coursed along the left side of the sac. The ascending colon did not show retroperitoneal
fixation.
The entrapped, viable small gut was brought to the right side through the hernial
ring after skeletonizing the IMV; the redundant sac was excised after closing the
hernial ring. Appendicectomy was also performed. Postoperative recovery was uneventful.
Mesocolic hernias are a rare congenital internal hernia arising from an error of rotation
of the midgut when the small bowel invaginates into the mesocolon as the later undergoes
rotation and retroperitoneal fixation. Failure of rotation of the pre-arterial segment
of the midgut around the superior mesenteric artery in the presence of normal rotation
of the post-arterial segment results in right mesocolic hernia, where the small gut
remains trapped behind the right mesocolon, in the right upper quadrant of the abdomen.4
On the other hand, left mesocolic hernia, as in our case, results when the small bowel
rotates to the left superior portion of the abdominal cavity between the IMV and the
retropritoneum, and during this process invaginates an avascular portion of the descending
mesocolon before the later gets fixed to the retroperitoneum.4 Thus the IMV forms
the anterior margin of the narrow hernial ring.
Congenital mesocolic hernias and herniations into one of the paraduodenal fossae are
two distinct clinical entities. The later results from herniations into small peritoneal
recesses formed due to abnormal fixation of the fourth part of duodenum.4 In either
case, preoperative diagnoses of these internal hernias are difficult.2,3
Though in this reported case the herniated loops of small gut could be reduced easily,
it may not be so easy. Sometimes the hernial orifice may be difficult to identify
and the engorged IMV may make the reduction potentially dangerous.4 Sometimes it may
be necessary to sacrifice the inferior mesenteric vessels to reduce the hernia5 though
most of the time this is unnecessary,1,2 provided the IMV is properly skeletonized
on the right margin and then reduction is attempted. Following reduction the IMV returns
to the left of the base of the mesentry of small bowel. Appendicectomy is always performed
to avoid any future diagnostic confusion arising from the abnormal position of the
caecum.
This is a case report of an 11-year-old boy with left mesocolic hernia. This condition is very similar to peritoneal encapsulation and a literature review of both conditions is done. Confusion among authors in naming them accordingly is addressed.
Publisher:
King Faisal Specialist Hospital and Research Centre
ISSN
(Print):
0256-4947
ISSN
(Electronic):
0975-4466
Publication date
(Print):
Sep-Oct 2005
Volume: 25
Issue: 5
Pages: 437-438
Author notes
Correspondence: Dr. Prosanta Kr. Bhattacharjee, R.G. Kar Medical College and Hospital,
Department Of Surgery, Kolkata-700004 India,
prosantabh@
123456rediffmail.com