DOI:10.2214/AJR.05.0080
AJR 2006; 186:906-907
© American Roentgen Ray Society
Perforated Appendix Within a Femoral Hernia
Nicholas D'Ambrosio1,
Douglas Katz2 and
John Hines3
1 Long Island Jewish Medical Center New Hyde Park, NY 11040
2 Winthrop-University Hospital Mineola, NY 11501
3 Long Island Jewish Medical Center New Hyde Park, NY 11040
A 71-year-old woman was evaluated in the emergency department for a mass in
the proximal right thigh that had grown in size over the past 2 weeks. She
complained of fever for 1 week and decreased appetite but no abdominal pain.
Physical examination revealed an 11-cm erythematous and indurated right
inguinal mass that was tender on palpation. Laboratory data were remarkable
only for leukocytosis with a WBC of 22,700/µL. Differential diagnosis at
this point of the workup included groin abscess and incarcerated hernia.
CT of the abdomen and pelvis extending inferiorly to cover the lower
inguinal area and upper thighs was performed with oral and IV contrast
material. This procedure showed a normal-appearing small intestine without
evidence of bowel obstruction. The cecum, however, was low in position, with
its base either within or in close proximity to a femoral hernia. There was
focal wall thickening of the caput cecum, which was in contact with a large
inflammatory mass (Fig. 3A).
This mass extended inferiorly into the hernia (Figs.
3B and
3C) and contained extraluminal
oral contrast material, fluid, and small pockets of gas. The appendix was not
identified. The diagnosis of perforated appendicitis and abscess formation
within a right femoral hernia was made and subsequently confirmed at emergent
surgery, during which a strangulated femoral hernia containing cecum,
perforated appendix, and abscess was found. A right hemicolectomy and abscess
drainage were performed.
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Fig. 3A —71-year-old woman with erythematous right groin mass. CT image
through pelvis at level of caput cecum shows oral contrast material containing
phlegmon (white arrows) abutting cecum (arrowheads) at
expected site of appendiceal orifice. Incidental note is made of large cystic
left adnexal mass (black arrow.)
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Fig. 3B —71-year-old woman with erythematous right groin mass. Image obtained
3.5 cm. caudad to A shows oral contrast material and gas-containing
collection (arrows) passing into femoral hernia in proximal thigh.
Note more lateral location of hernia than would be expected with inguinal
hernia.
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Fig. 3C —71-year-old woman with erythematous right groin mass. Slightly more
caudad image through right groin again shows large volume of oral contrast
material and gas-containing inflammatory collection (arrows).
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The presence of the appendix within a hernia sac is an infrequent finding
but has been well documented in the surgical literature
[1,
2]. Such findings can occur
within inguinal (Amyand's hernia), femoral, incisional, or spigelian hernias.
Femoral hernias are thought to be due to a congenital defect and occur much
more commonly in women [1].
Because of the narrowness and rigidity of the femoral canal, the rate of
incarceration in femoral hernias (14-56%) is significantly higher than in
inguinal hernias (6-10%), and it therefore requires early surgical repair
[1]. Herniation of the appendix
into a femoral hernia sac was first reported by DeGarengot in 1731
[2] and occurred with a
frequency of less than 1% in one large series
[1].
Acute appendicitis within an external hernia accounts for 0.13% of all
cases of acute appendicitis
[3]. The cause of appendicitis
in this case is left to speculation because the appendix was perforated at
surgery. Theoretically, it could be due to either an intrinsic or extrinsic
obstruction. However, it is thought that the cause of acute appendicitis
within femoral hernias is most commonly external compression of the appendix
at the neck of the hernia [2,
4] rather than the intraluminal
obstruction typically seen when the appendix is within the peritoneal cavity.
As seen in this case, when the appendix alone is strangulated by the hernia,
there will be no bowel obstruction. The narrowness and rigidity of the femoral
canal usually prevent intraperitoneal spread of infection, and therefore the
patient will not present with symptoms of peritonitis but rather local signs
such as erythema, redness, and groin tenderness.
Before the widespread use of CT, the diagnosis of acute appendicitis within
an external hernia was almost never made before surgery, often being mistaken
for an incarcerated hernia. However, there have been scattered case reports in
the imaging literature describing the prospective CT diagnosis of acute
appendicitis within inguinal or femoral hernias
[3,
4]. To the best of our
knowledge, all previous reports have involved an intact appendix. This is the
first report of perforated appendicitis within such a hernia being
prospectively diagnosed using CT. That the appendix may not be easily
visualized or may not be visualized at all on CT secondary to perforation
makes interpretation more difficult than in cases of an intact appendix.
Recognition of the location of the cecum within the hernia sac and the
inflammatory collection in the expected location of the appendix is helpful in
arriving at the diagnosis, although other entities, such as cecal
diverticulitis or perforated cecal neoplasm, could have the same appearance.
The location of the hernia lateral and inferior in relation to the pubic
tubercle speaks for a femoral rather than inguinal hernia, the latter of which
is usually found medial and superior in relation to the pubic tubercle
[4].
In conclusion, we have presented a case of perforated appendicitis and
abscess formation within a femoral hernia, described its findings on CT, and
shown the utility of CT in suggesting this unusual diagnosis.
References
- Cordera F, Sarr MG. Incarcerated appendix in a femoral hernia sac.
Contemp Surg 2003;59
: 35-37
- Nguyen ET, Komenaka IK. Strangulated femoral hernia containing a
perforated appendix. Can J Surg 2004;47
: 68-69[Medline]
- Luchs JS, Halpern D, Katz DS. Amyand's hernia: prospective CT
diagnosis. J Comput Assist Tomogr 2000;24
: 884-886[Medline]
- Zissin R, Brautbar O, Shapiro-Feinberg M. CT diagnosis of acute
appendicitis in a femoral hernia. Br J Radiol2000; 73:1013
-1014[Abstract]
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