Department of Gastroenterology and Digestive Endoscopy, Jewish Hospital of Rome. Via Fulda 14, Rome 00100, ItalyItaly
Department of Oncological Surgery, Ospedale San Camillo-Forlanini. Via Portuense 332, Rome 00151, ItalyItaly
Department of Radiology, Jewish Hospital of Rome. Via Fulda 14, Rome 00100, ItalyItaly
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Crohn’s Disease (CD) is a chronic inflammatory disorder of the intestinal tract characterized by trans-mural damage of the bowel wall often complicated by strictures, entero-visceral and perianal fistulae and abscesses. Both computed tomography and magnetic resonance enable clear visualization of the involved intestinal tract together with various extra- and intra intestinal complications. Herewith, the uncommon case of a hidden retroperitoneal abscess with para-vertebral collection, as a consequence of a penetrating CD of the terminal ileum, is described. Retrofascial collections, due to fistulizing CD, are rare events often misdiagnosed or even recognized late in the clinical course and associated with severe and potentially life threatening consequences. Prompt assessment with cross-sectional imaging is necessary. MR imaging is being more frequently used in the follow-up of CD since the lack of ionizing radiations which avoids any biological impact in these patients.
Keywords: Crohn’s disease; Inflammatory bowel disease; Intestinal tract
perivisceral fistulae. roperitoneal space, below the right kidney.
CD is a chronic inflammatory disorder which may
involve any segment of the Gastrointestinal (GI) tract and
which is characterized by trans-mural damage of the bowel
wall.1 The incidence of CD is approximately 5-10 new cases
per 100,000 individuals/year and is known to follow an un-
predictable course with periodic exacerbations.2 Although the
terminal ileum is the most common site of CD and upper GI
involvement is rare, multiple non-contiguous segments of the
small bowel may be involved.3 Since CD is characterized by
tory or fibromatous process is often difficult but is essential
collection was detected in this area. Computed Tomography (CT) for appropriate clinical management (i.e., medical vs. surgical
treatment).4 was performed to further investigate these findings which re-
vealed, in the retrofascial space, an abscess measuring 6 cm by 5 MRI provides a definite soft tissue contrast resolu-
fibrotic characteristics of the bowel wall. Normal bowel thickretroperitoneum is a space between the peritoneum and trans-
versalis fascia which lines the posterior abdominal cavity. It ness is considered to be ≤3 mm. With time, common compli-
cations of small-bowel CD may include bowel obstructions, extends laterally to the edges of the quadratus lumbar mus-
fistulae and abscesses.
cles, the diaphragm above and the pelvic brim below. The ret-
roperitoneum is divided into an anterior space containing the
Fistulae may act as a bridge to adjacent loops of the colon, duodenum, and pancreas and a posterior space in which
small bowel or from the small bowel to the colon, stomach, kidneys, aorta, and inferior vena cava are found. The area is
bladder and skin. In population based studies, fistula formaclosed above but is open below thus allowing retro-peritoneal
1,2 infections to be bilateral and extend to the pelvis and thighs. tion has been reported in 17-50% of patients with CD. Ac-
cording to an epidemiologic study, 35% of the CD patients The retrofascial space which is located between the transver-
develop at least one fistula episode during the course of the salis fascia and the posterior parietal wall contains the spinal
disease. Of these fistulae, approximately two thirds are exand para-vertebral musculature. This area extends above into
ternal (perianal 55%, enterocutaneous 6%) and one third are the mediastinum and below into the pelvis and thighs. Infec-
tions of the retrofascial area that are not strictly in the retinternal. Penetrating disease may cause the formation of
abscesses which can often be treated by a percutaneous aproperitoneal space are included in the differential diagnosis
proach. The presence of penetrating disease, in the absence of the retro-peritoneal abscess. Thus, infections and inflam-
of a collection, often influences the medical approach; clinimatory processes of any of these anatomical structures may
cians, usually avoid the use of steroids in such cases and may, result in a retro-peritoneal abscess. Abscesses resulting from
instead, consider antibiotic or biologic therapy.
deep fissuring of the bowel wall or suppuration within lymph
nodes and local fistulation, develop in approximately 20% of
1,2 Fistulae occur as the result of deep transmural ul- CD patients.1,2 Several cases of vertebral and para-vertebral
cers or fissures that eventually penetrate the bowel layers and infection have been described in association with enteric fis-
cause inflammation in the adjacent mesenteric tissue leading tulae.14 Isolated discitis, however, has rarely been reported.
to formation of small abscesses and blind-ending sinus tracts.
Upon CT and MRI, fistulae appear as extra-enteric enhancing In conclusion, we describe the unusual case of a hid-
tracts which may or may not contain fluid.
den retroperitoneal abscess with para-vertebral collection as a
consequence of a penetrating CD of the terminal ileum, em-
Recent advances in CT and MR imaging (MRI) ofphasizing the importance of complete radiological work-up
fer excellent visualization of the small bowel wall and lumen in these patients and the need for a careful clinical and surgi-
when the organ is appropriately distended using an enteric cal evaluation in order to define the most appropriate medical
contrast. In particular, these techniques can reveal small treatment in such cases.
bowel inflammation and complications (e.g., strictures, fis-
tulae, abscesses). Furthermore, MRI is becoming more and
more important as a diagnostic tool in the work-up of CD, Renato Caviglia and Basilio Lippi contributed equally to this given the lack of ionizing radiations, considering that these article. Angelo Di Castro and Claudio Cannaviello collected examinations are performed frequently during the follow-up the medical data and read and approved the manuscript. of these patients. Several studies have also shown that the
MRI technique defines not only the site but also the degree of CD activity, by evaluating the increased enhancement of
the involved bowel wall by means of contrast T1-weighted
6-12 sequences. Horsthuis et al. performed a meta-analysis and
reported that there was no statistically significant difference
between MRI and CT in the detection of inflammatory bowel
disease, including extra-enteric complications.
The retroperitoneal abscess is a relatively rare con-
dition and is often misdiagnosed or even recognized late in
the clinical course. It is a severe infection which is associ-
ated with significant mortality but early diagnosis and treat-
ment considerably reduce the morbidity and mortality rates.
Recognition of the condition and the likely etiological factors
would increase awareness and, therefore, early surgical drain-
age would significantly improve clinical outcome.
Herewith, we presented an illustrative case of fis-
The Authors are grateful to Mrs. Marian Shields for helping
with the preparation of the manuscript as well as the lan-
guage.
The authors have no conflicts of interest to declare.
Did the authors obtain written informed consent from the pa-
tient for submission of this manuscript for publication? Yes