- Email: [email protected]
Primary retroperitoneal fasciitis; A rare cause of acute abdominal pain
Accepted Manuscript Primary retroperitoneal fasciitis; A rare cause of acute abdominal pain
Emre Ünal, Mehmet Ruhi Onur, Erhan Akpinar, Musturay Karcaaltincaba PII: DOI: Reference:
S0735-6757(17)30164-X doi: 10.1016/j.ajem.2017.02.050 YAJEM 56516
To appear in: Received date: Revised date: Accepted date:
25 February 2017 26 February 2017 28 February 2017
Please cite this article as: Emre Ünal, Mehmet Ruhi Onur, Erhan Akpinar, Musturay Karcaaltincaba , Primary retroperitoneal fasciitis; A rare cause of acute abdominal pain. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Yajem(2017), doi: 10.1016/j.ajem.2017.02.050
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT 1
Primary retroperitoneal fasciitis; a rare cause of acute abdominal pain
1
1
Hacettepe University, School of Medicine, Department of Radiology, Ankara, Turkey, 06100
AN
1
1
US
Musturay Karcaaltincaba, MD, Professor
IP
Erhan Akpinar, MD, Professor
1
T
Mehmet Ruhi Onur, MD, Associate Professor
CR
Emre Ünal, MD,
M
E-mail adresses:
ED
1) Emre Ünal 2) Mehmet Ruhi Onur
PT
3) Erhan Akpinar
[email protected] [email protected] [email protected]
CE
4) Musturay Karcaaltincaba
[email protected]
Corresponding author : Emre Unal
AC
Hacettepe University, School of Medicine, Department of Radiology, Ankara, Turkey, 06100 Phone: +90 312 305 1188 / 305 4160 Fax: +90 312 311 2145 Email : [email protected]
Conflicts of Interest and Source of Funding: None. Authors declare that they have no conflict of interest. The authors received no financial support for the research, authorship, and/or publication of this article.
ACCEPTED MANUSCRIPT 2
Abstract The retroperitoneal fascial planes can be affected by various clinical disorders. In most of the cases retroperitoneal involvement occurs secondary to spread of a distinct underlying etiology. Herein we report two cases of primary retroperitoneal fasciitis diagnosed with imaging findings. The diagnosis of retroperitoneal fasciitis should be made by exclusion since various and more
appendicitis may present with similar imaging findings.
AC
CE
PT
ED
M
AN
US
CR
Keywords: Retroperitoneum, fasciitis, acute abdomen, CT, MRI
IP
T
frequently encountered disorders including acute pancreatitis, duodenitis, pyelonephritis, and
ACCEPTED MANUSCRIPT 3
Introduction The peritoneum is a serous membrane that surrounds the abdominal cavity with two different layers. The visceral part of the peritoneum wraps around visceral organs and parietal part surrounds the abdominal cavity [1]. The abdominal pathologies are restricted to a specific region in most cases, due to boundary effect of the peritoneum [1, 2]. Although most of the clinical
T
disorders affect intraperitoneal region, the retroperitoneal space can also be involved by a variety
IP
of conditions, including infectious, inflammatory, and neoplastic types of etiologies [2, 3]. The
CR
retroperitoneal fascial planes are secondarily involved in most cases. Herein, we report two cases of primary retroperitoneal fasciitis without an underlying source of infection. There is lack of
US
data in the literature regarding the imaging features of primary retroperitoneal fasciitis, to the best of our knowledge.
AN
Case reports
M
Case 1
A 43-year-old man was admitted to emergency department with a 5-day history of abdominal
ED
pain, nausea, and vomiting. He had history of diabetes for 5 years and Familial Mediterranean Fever (FMF) for over 10 years. He was under treatment with colchicine for FMF and was
PT
asymptomatic for over a year. The main presenting symptoms of FMF episodes were joint pain and fever. On admission, he was febrile (38.5°C) and had a fibrinogen level of 910 mg/dL. He
CE
had normal white blood cell (WBC) counts, serum amylase and lipase levels, liver and kidney function tests. On follow-up the abdominal pain was localized to right lower quadrant and he also
AC
developed mild cough and yellow phlegm production. Diffuse abdominal tenderness and rebound were evident on physical examination. Initial ultrasonography (US) scan revealed extensive fluid collection extending from periduodenal area through to right lower quadrant (Fig. 1). Control CT and MRI scans confirmed sonographic findings with also providing better demonstration of the involvement through the course of retroperitoneal fascia (Figs. 1 and 2). Considerable amounts of inflammatory and phlegmonous changes were noted in the retroperitoneal space. Inflammatory fluid collection was arising from anterior pararenal space and extending to the pelvis by traversing lateroconal and retrorenal planes. Laboratory findings excluded the diagnosis of acute pancreatitis. Upper gastrointestinal endoscopy and colonoscopy were unremarkable.
ACCEPTED MANUSCRIPT 4
Percutaneous aspiration of the fluid collection was carried out and the culture test was positive for Klebsiella pneumoniae. Following adequate antibiotherapy both the imaging and clinical findings demonstrated significant regression without requiring surgery Case 2 A 43- year-old man was referred to emergency department with a 2-day history of right
T
costovertebral angle tenderness and ketoacidosis. He had a history of diabetes with unknown
IP
duration. On admission, he was afebrile and had a mildly elevated level of WBC (12.700 mm3).
CR
He had right costovertebral angle and right lower quadrant tenderness on physical examination. Serum amylase and lipase levels, liver and kidney function tests were unremarkable. CT scan was
US
obtained to rule out renal pathologies and acute appendicitis. However CT demonstrated severe fat tissue stranding and inflammation through the course of retroperitoneal fascia with also
AN
affecting the right anterior pararenal and perirenal spaces with lateroconal and retrorenal plane involvement (Fig. 3). There was no sign of acute appendicitis, nephrolithiasis, and pyelonephritis on CT images. Primary retroperitoneal fasciitis was considered for the diagnosis, however, the
M
patient refused further evaluation and was lost on follow-up period.
ED
Discussion
Peritonitis is a relatively common condition compared to retroperitoneal fasciitis. However both
PT
conditions have been reported to occur secondary to various clinical etiologies that may spread through the peritoneal fascial planes [1-3]. Retroperitoneal fasciitis is recognized as a severe
CE
clinical setting that urgent surgical intervention is indicated in most of the cases. Herein we reported two cases of primary retroperitoneal fasciitis without an underlying source of infection.
AC
One patient was lost on follow-up, however the other patient was able to be treated without requiring surgery. Awareness of imaging findings is the mainstay issue in the diagnosis of retroperitoneal fasciitis. CT and MRI features of retroperitoneal fasciitis include asymmetric fascial thickening and enhancement, muscular edema, fat stranding, gas tracking along fascial planes in the retroperitoneum, transgression of fascial planes, fluid collections and abscess formation. Abovementioned imaging findings were suggestive of the diagnosis of retroperitoneal fasciitis in our cases.
ACCEPTED MANUSCRIPT 5
Depending on our observation, we argue that retroperitoneal fascia can be the primary site of infection in rare cases. However, it should be emphasized that the diagnosis should be made by exclusion. Symptoms of patients with retroperitoneal fasciitis may easily mimic other causes of acute abdominal disorders since patients experience disproportionate pain secondary to intramuscular edema and inflammatory involvement of nerves resulting in compartment
T
syndrome [2]. Various types of etiologies including acute pancreatitis, duodenitis, and
IP
pyelonephritis may induce similar imaging findings [2]. Moreover, acute appendicitis should also be considered as a differential diagnosis, due to close relation to retroperitoneal area in right
CR
lower quadrant. It may be argued that primary retroperitoneal fasciitis may be an underrated
with acute pancreatitis, duodenitis or appendicitis.
US
cause of acute abdomen and its incidence may be underestimated due to misdiagnosis of patients
AN
Necrotizing type of retroperitoneal fasciitis is recognized with gas bubbles seen through the fascial planes along with the inflammation. In the literature, surgery is considered as the main treatment option in most of the cases with necrotizing type of retroperitoneal fasciitis, since
M
almost all of the cases have an underlying primary source of infection spreads through the
ED
retroperitoneal fascia [2] Herein reported case had primary retroperitoneal fasciitis and responded to antibiotherapy without the need for surgery. However, we could not determine the exact
PT
pathophysiology of retroperitoneal fasciitis. Both patients had diabetes and one had FMF that was asymptomatic for over a year. It is not surprising that patients with diabetes are at risk for
CE
increased rate of infection. On the other hand, presence of FMF may have increased the rate of peritonitis and fasciitis. However the course of inflammation through the retroperitoneal fascia was atypical for an episode of FMF [4, 5]. Moreover microorganism containing abdominal fluid
AC
collection is also unusual for patients with FMF. Therefore, an acute episode of FMF was less likely the main cause for acute abdominal pain. Percutaneous aspiration of the fluid collection revealed Klebsiella pneumonia which is a significant pathogen for respiratory tract infections. This patient also developed mild cough and yellow phlegm production on follow-up, yet chest imaging findings were unremarkable. In a study by Moustaki et al [6], authors reported that mesenteric lymphadenopathy could be a cause of abdominal pain in children with pneumonia. Reach capillary network of the lymphatic system may be the reason for abdominal lymphadenopathy in these patients, as both thoracic and abdominal cavities’ lymphatic vessels
ACCEPTED MANUSCRIPT 6
are indirectly related to each other via ductus thoracicus. Therefore, it may be suggested that the lymphatic system may have facilitated the fascial inflammation in our case by enabling Klebsiella pneumonia spread from respiratory tract to abdominal cavity. However we were not able to prove this hypothesis, and further studies are warranted for clarifying the relationship of respiratory tract lymphatic system with retroperitoneal fascia.
T
Differentiation non-necrotizing retroperitoneal fasciitis from necrotizing type of retroperitoneal
IP
fasciitis is utmost important due to necessity of aggressive treatment with surgery in necrotizing
CR
type. Contribution of MRI findings may be helpful in differentiation of these two entities. Kim et al. [7] reported that necrotizing retroperitoneal fasciitis manifest with a higher frequency of deep
US
fascial thickening greater than 3 mm, abnormal low signal intensity in the deep fascia representing presumably air and focal or diffuse nonenhancement of the abnormal deep fascia on
AN
contrast-enhanced T1-weighted images. MRI features of our cases were suggestive of nonnecrotizing retroperitoneal fasciitis which was supported by the presence of response to medical
M
treatment.
In conclusion, the retroperitoneal fascia can be involved as a primary site of infection in rare
ED
cases and the diagnosis should be made by exclusion. Various and more frequently encountered clinical conditions including acute pancreatitis, duodenitis, pyelonephritis, and appendicitis
PT
comprise the main list of differential diagnosis. A high index of suspicion and awareness of imaging findings are crucial for the diagnosis of retroperitoneal fasciitis in patients with
AC
CE
inordinate abdominal pain.
All authors declare that they have no conflict of interest. The authors received no financial support for the research, authorship, and/or publication of this article.
ACCEPTED MANUSCRIPT 7
References 1.
Tirkes T, Sandrasegaran K, Patel AA, Hollar MA, Tejada JG, Tann M, et al. Peritoneal and retroperitoneal anatomy and its relevance for cross-sectional imaging. Radiographics 2012; 32:437-51
2.
Chingkoe CM, Jahed A, Loreto MP, Sarrazin J, McGregor CT, Blaichman JI, et al.
IP
T
Retroperitoneal Fasciitis: Spectrum of CT Findings in the Abdomen and Pelvis. Radiographics 2015; 35:1095-107
Nishino M, Hayakawa K, Minami M, Yamamoto A, Ueda H, Takasu K. Primary
CR
3.
retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic
4.
US
diagnostic clues. Radiographics 2003; 23:45-57
Aharoni D, Hiller N, Hadas-Halpern I. Familial Mediterranean fever: abdominal imaging
5.
AN
findings in 139 patients and review of the literature. Abdom Imaging 2000; 25:297-300 Ishak GE, Khoury NJ, Birjawi GA, El-Zein YR, Naffaa LN, Haddad MC. Imaging findings of
Moustaki M, Zeis PM, Katsikari M, Fretzayas A, Grafakou O, Stabouli S, et al. Mesenteric
ED
6.
M
familial Mediterranean fever. Clin Imaging 2006; 30:153-9
lymphadenopathy as a cause of abdominal pain in children with lobar or segmental
Kim KT, Kim YJ, Won Lee J, Kim YJ, Park SW, Lim MK, et al. Can necrotizing infectious
CE
fasciitis be differentiated from nonnecrotizing infectious fasciitis with MR imaging? Radiology 2011; 259:816-24
AC
7.
PT
pneumonia. Pediatr Pulmonol 2003; 35:269-73
ACCEPTED MANUSCRIPT 8
Figure legends Fig. 1 Axial US (upper row) and corresponding CT images (lower row) demonstrate multiseptated extensive fluid collection (white arrows) and fat tissue inflammation (black arrows) extending from anterior pararenal space and retromezenteric plane to the subperitoneal space in the pelvis by traversing lateroconal plane, interfascial plane and posterior pararenal space. A
T
diagnosis of primary retroperitoneal fasciitis was made by imaging findings. A culture test
IP
following percutaneous needle (short arrows) aspiration was positive for Klebsiella pneumonia.
CR
No other source of infection was evident on CT images. Note also post-operative soft tissue changes due to previous lipoma excision (asterisk).
US
A: Abdominal aorta
Fig. 2 Axial T2 (a), fat-suppressed T2 (b), and post contrast fat-suppressed T1 (c) weighted MR
AN
images clearly reveal inflammation, fascial thickening and fluid collections through the retroperitoneal fascial planes (arrows). Follow-up axial T2 (d) weighted MR image obtained 10
M
days after CT scan, reveals complete resolution of the findings.
ED
Fig. 3 Consecutive axial contrast enhanced CT images demonstrate extensive fat tissue stranding and mild fluid loculations (long arrows) through the course of thickened retroperitoneal fascia
PT
(asterisk) with involvement of right anterior pararenal and perirenal spaces, lateroconal, retrorenal and interfascial planes. The perirenal fascial planes are secondarily affected (short
AC
CE
arrows).
ACCEPTED MANUSCRIPT
CR
IP
T
9
AC
CE
PT
ED
M
AN
US
Figure 1
ACCEPTED MANUSCRIPT
AN
US
CR
IP
T
10
AC
CE
PT
ED
M
Figure 2
ACCEPTED MANUSCRIPT
AN
US
CR
IP
T
11
AC
CE
PT
ED
M
Figure 3
Emre Ünal, Mehmet Ruhi Onur, Erhan Akpinar, Musturay Karcaaltincaba PII: DOI: Reference:
S0735-6757(17)30164-X doi: 10.1016/j.ajem.2017.02.050 YAJEM 56516
To appear in: Received date: Revised date: Accepted date:
25 February 2017 26 February 2017 28 February 2017
Please cite this article as: Emre Ünal, Mehmet Ruhi Onur, Erhan Akpinar, Musturay Karcaaltincaba , Primary retroperitoneal fasciitis; A rare cause of acute abdominal pain. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Yajem(2017), doi: 10.1016/j.ajem.2017.02.050
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT 1
Primary retroperitoneal fasciitis; a rare cause of acute abdominal pain
1
1
Hacettepe University, School of Medicine, Department of Radiology, Ankara, Turkey, 06100
AN
1
1
US
Musturay Karcaaltincaba, MD, Professor
IP
Erhan Akpinar, MD, Professor
1
T
Mehmet Ruhi Onur, MD, Associate Professor
CR
Emre Ünal, MD,
M
E-mail adresses:
ED
1) Emre Ünal 2) Mehmet Ruhi Onur
PT
3) Erhan Akpinar
[email protected] [email protected] [email protected]
CE
4) Musturay Karcaaltincaba
[email protected]
Corresponding author : Emre Unal
AC
Hacettepe University, School of Medicine, Department of Radiology, Ankara, Turkey, 06100 Phone: +90 312 305 1188 / 305 4160 Fax: +90 312 311 2145 Email : [email protected]
Conflicts of Interest and Source of Funding: None. Authors declare that they have no conflict of interest. The authors received no financial support for the research, authorship, and/or publication of this article.
ACCEPTED MANUSCRIPT 2
Abstract The retroperitoneal fascial planes can be affected by various clinical disorders. In most of the cases retroperitoneal involvement occurs secondary to spread of a distinct underlying etiology. Herein we report two cases of primary retroperitoneal fasciitis diagnosed with imaging findings. The diagnosis of retroperitoneal fasciitis should be made by exclusion since various and more
appendicitis may present with similar imaging findings.
AC
CE
PT
ED
M
AN
US
CR
Keywords: Retroperitoneum, fasciitis, acute abdomen, CT, MRI
IP
T
frequently encountered disorders including acute pancreatitis, duodenitis, pyelonephritis, and
ACCEPTED MANUSCRIPT 3
Introduction The peritoneum is a serous membrane that surrounds the abdominal cavity with two different layers. The visceral part of the peritoneum wraps around visceral organs and parietal part surrounds the abdominal cavity [1]. The abdominal pathologies are restricted to a specific region in most cases, due to boundary effect of the peritoneum [1, 2]. Although most of the clinical
T
disorders affect intraperitoneal region, the retroperitoneal space can also be involved by a variety
IP
of conditions, including infectious, inflammatory, and neoplastic types of etiologies [2, 3]. The
CR
retroperitoneal fascial planes are secondarily involved in most cases. Herein, we report two cases of primary retroperitoneal fasciitis without an underlying source of infection. There is lack of
US
data in the literature regarding the imaging features of primary retroperitoneal fasciitis, to the best of our knowledge.
AN
Case reports
M
Case 1
A 43-year-old man was admitted to emergency department with a 5-day history of abdominal
ED
pain, nausea, and vomiting. He had history of diabetes for 5 years and Familial Mediterranean Fever (FMF) for over 10 years. He was under treatment with colchicine for FMF and was
PT
asymptomatic for over a year. The main presenting symptoms of FMF episodes were joint pain and fever. On admission, he was febrile (38.5°C) and had a fibrinogen level of 910 mg/dL. He
CE
had normal white blood cell (WBC) counts, serum amylase and lipase levels, liver and kidney function tests. On follow-up the abdominal pain was localized to right lower quadrant and he also
AC
developed mild cough and yellow phlegm production. Diffuse abdominal tenderness and rebound were evident on physical examination. Initial ultrasonography (US) scan revealed extensive fluid collection extending from periduodenal area through to right lower quadrant (Fig. 1). Control CT and MRI scans confirmed sonographic findings with also providing better demonstration of the involvement through the course of retroperitoneal fascia (Figs. 1 and 2). Considerable amounts of inflammatory and phlegmonous changes were noted in the retroperitoneal space. Inflammatory fluid collection was arising from anterior pararenal space and extending to the pelvis by traversing lateroconal and retrorenal planes. Laboratory findings excluded the diagnosis of acute pancreatitis. Upper gastrointestinal endoscopy and colonoscopy were unremarkable.
ACCEPTED MANUSCRIPT 4
Percutaneous aspiration of the fluid collection was carried out and the culture test was positive for Klebsiella pneumoniae. Following adequate antibiotherapy both the imaging and clinical findings demonstrated significant regression without requiring surgery Case 2 A 43- year-old man was referred to emergency department with a 2-day history of right
T
costovertebral angle tenderness and ketoacidosis. He had a history of diabetes with unknown
IP
duration. On admission, he was afebrile and had a mildly elevated level of WBC (12.700 mm3).
CR
He had right costovertebral angle and right lower quadrant tenderness on physical examination. Serum amylase and lipase levels, liver and kidney function tests were unremarkable. CT scan was
US
obtained to rule out renal pathologies and acute appendicitis. However CT demonstrated severe fat tissue stranding and inflammation through the course of retroperitoneal fascia with also
AN
affecting the right anterior pararenal and perirenal spaces with lateroconal and retrorenal plane involvement (Fig. 3). There was no sign of acute appendicitis, nephrolithiasis, and pyelonephritis on CT images. Primary retroperitoneal fasciitis was considered for the diagnosis, however, the
M
patient refused further evaluation and was lost on follow-up period.
ED
Discussion
Peritonitis is a relatively common condition compared to retroperitoneal fasciitis. However both
PT
conditions have been reported to occur secondary to various clinical etiologies that may spread through the peritoneal fascial planes [1-3]. Retroperitoneal fasciitis is recognized as a severe
CE
clinical setting that urgent surgical intervention is indicated in most of the cases. Herein we reported two cases of primary retroperitoneal fasciitis without an underlying source of infection.
AC
One patient was lost on follow-up, however the other patient was able to be treated without requiring surgery. Awareness of imaging findings is the mainstay issue in the diagnosis of retroperitoneal fasciitis. CT and MRI features of retroperitoneal fasciitis include asymmetric fascial thickening and enhancement, muscular edema, fat stranding, gas tracking along fascial planes in the retroperitoneum, transgression of fascial planes, fluid collections and abscess formation. Abovementioned imaging findings were suggestive of the diagnosis of retroperitoneal fasciitis in our cases.
ACCEPTED MANUSCRIPT 5
Depending on our observation, we argue that retroperitoneal fascia can be the primary site of infection in rare cases. However, it should be emphasized that the diagnosis should be made by exclusion. Symptoms of patients with retroperitoneal fasciitis may easily mimic other causes of acute abdominal disorders since patients experience disproportionate pain secondary to intramuscular edema and inflammatory involvement of nerves resulting in compartment
T
syndrome [2]. Various types of etiologies including acute pancreatitis, duodenitis, and
IP
pyelonephritis may induce similar imaging findings [2]. Moreover, acute appendicitis should also be considered as a differential diagnosis, due to close relation to retroperitoneal area in right
CR
lower quadrant. It may be argued that primary retroperitoneal fasciitis may be an underrated
with acute pancreatitis, duodenitis or appendicitis.
US
cause of acute abdomen and its incidence may be underestimated due to misdiagnosis of patients
AN
Necrotizing type of retroperitoneal fasciitis is recognized with gas bubbles seen through the fascial planes along with the inflammation. In the literature, surgery is considered as the main treatment option in most of the cases with necrotizing type of retroperitoneal fasciitis, since
M
almost all of the cases have an underlying primary source of infection spreads through the
ED
retroperitoneal fascia [2] Herein reported case had primary retroperitoneal fasciitis and responded to antibiotherapy without the need for surgery. However, we could not determine the exact
PT
pathophysiology of retroperitoneal fasciitis. Both patients had diabetes and one had FMF that was asymptomatic for over a year. It is not surprising that patients with diabetes are at risk for
CE
increased rate of infection. On the other hand, presence of FMF may have increased the rate of peritonitis and fasciitis. However the course of inflammation through the retroperitoneal fascia was atypical for an episode of FMF [4, 5]. Moreover microorganism containing abdominal fluid
AC
collection is also unusual for patients with FMF. Therefore, an acute episode of FMF was less likely the main cause for acute abdominal pain. Percutaneous aspiration of the fluid collection revealed Klebsiella pneumonia which is a significant pathogen for respiratory tract infections. This patient also developed mild cough and yellow phlegm production on follow-up, yet chest imaging findings were unremarkable. In a study by Moustaki et al [6], authors reported that mesenteric lymphadenopathy could be a cause of abdominal pain in children with pneumonia. Reach capillary network of the lymphatic system may be the reason for abdominal lymphadenopathy in these patients, as both thoracic and abdominal cavities’ lymphatic vessels
ACCEPTED MANUSCRIPT 6
are indirectly related to each other via ductus thoracicus. Therefore, it may be suggested that the lymphatic system may have facilitated the fascial inflammation in our case by enabling Klebsiella pneumonia spread from respiratory tract to abdominal cavity. However we were not able to prove this hypothesis, and further studies are warranted for clarifying the relationship of respiratory tract lymphatic system with retroperitoneal fascia.
T
Differentiation non-necrotizing retroperitoneal fasciitis from necrotizing type of retroperitoneal
IP
fasciitis is utmost important due to necessity of aggressive treatment with surgery in necrotizing
CR
type. Contribution of MRI findings may be helpful in differentiation of these two entities. Kim et al. [7] reported that necrotizing retroperitoneal fasciitis manifest with a higher frequency of deep
US
fascial thickening greater than 3 mm, abnormal low signal intensity in the deep fascia representing presumably air and focal or diffuse nonenhancement of the abnormal deep fascia on
AN
contrast-enhanced T1-weighted images. MRI features of our cases were suggestive of nonnecrotizing retroperitoneal fasciitis which was supported by the presence of response to medical
M
treatment.
In conclusion, the retroperitoneal fascia can be involved as a primary site of infection in rare
ED
cases and the diagnosis should be made by exclusion. Various and more frequently encountered clinical conditions including acute pancreatitis, duodenitis, pyelonephritis, and appendicitis
PT
comprise the main list of differential diagnosis. A high index of suspicion and awareness of imaging findings are crucial for the diagnosis of retroperitoneal fasciitis in patients with
AC
CE
inordinate abdominal pain.
All authors declare that they have no conflict of interest. The authors received no financial support for the research, authorship, and/or publication of this article.
ACCEPTED MANUSCRIPT 7
References 1.
Tirkes T, Sandrasegaran K, Patel AA, Hollar MA, Tejada JG, Tann M, et al. Peritoneal and retroperitoneal anatomy and its relevance for cross-sectional imaging. Radiographics 2012; 32:437-51
2.
Chingkoe CM, Jahed A, Loreto MP, Sarrazin J, McGregor CT, Blaichman JI, et al.
IP
T
Retroperitoneal Fasciitis: Spectrum of CT Findings in the Abdomen and Pelvis. Radiographics 2015; 35:1095-107
Nishino M, Hayakawa K, Minami M, Yamamoto A, Ueda H, Takasu K. Primary
CR
3.
retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic
4.
US
diagnostic clues. Radiographics 2003; 23:45-57
Aharoni D, Hiller N, Hadas-Halpern I. Familial Mediterranean fever: abdominal imaging
5.
AN
findings in 139 patients and review of the literature. Abdom Imaging 2000; 25:297-300 Ishak GE, Khoury NJ, Birjawi GA, El-Zein YR, Naffaa LN, Haddad MC. Imaging findings of
Moustaki M, Zeis PM, Katsikari M, Fretzayas A, Grafakou O, Stabouli S, et al. Mesenteric
ED
6.
M
familial Mediterranean fever. Clin Imaging 2006; 30:153-9
lymphadenopathy as a cause of abdominal pain in children with lobar or segmental
Kim KT, Kim YJ, Won Lee J, Kim YJ, Park SW, Lim MK, et al. Can necrotizing infectious
CE
fasciitis be differentiated from nonnecrotizing infectious fasciitis with MR imaging? Radiology 2011; 259:816-24
AC
7.
PT
pneumonia. Pediatr Pulmonol 2003; 35:269-73
ACCEPTED MANUSCRIPT 8
Figure legends Fig. 1 Axial US (upper row) and corresponding CT images (lower row) demonstrate multiseptated extensive fluid collection (white arrows) and fat tissue inflammation (black arrows) extending from anterior pararenal space and retromezenteric plane to the subperitoneal space in the pelvis by traversing lateroconal plane, interfascial plane and posterior pararenal space. A
T
diagnosis of primary retroperitoneal fasciitis was made by imaging findings. A culture test
IP
following percutaneous needle (short arrows) aspiration was positive for Klebsiella pneumonia.
CR
No other source of infection was evident on CT images. Note also post-operative soft tissue changes due to previous lipoma excision (asterisk).
US
A: Abdominal aorta
Fig. 2 Axial T2 (a), fat-suppressed T2 (b), and post contrast fat-suppressed T1 (c) weighted MR
AN
images clearly reveal inflammation, fascial thickening and fluid collections through the retroperitoneal fascial planes (arrows). Follow-up axial T2 (d) weighted MR image obtained 10
M
days after CT scan, reveals complete resolution of the findings.
ED
Fig. 3 Consecutive axial contrast enhanced CT images demonstrate extensive fat tissue stranding and mild fluid loculations (long arrows) through the course of thickened retroperitoneal fascia
PT
(asterisk) with involvement of right anterior pararenal and perirenal spaces, lateroconal, retrorenal and interfascial planes. The perirenal fascial planes are secondarily affected (short
AC
CE
arrows).
ACCEPTED MANUSCRIPT
CR
IP
T
9
AC
CE
PT
ED
M
AN
US
Figure 1
ACCEPTED MANUSCRIPT
AN
US
CR
IP
T
10
AC
CE
PT
ED
M
Figure 2
ACCEPTED MANUSCRIPT
AN
US
CR
IP
T
11
AC
CE
PT
ED
M
Figure 3