CASE 13676 Published on 02.06.2016

Necrotizing pancreatitis: peripancreatic necrosis alone

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Delgado-Moraleda JJ, Brugger-Frigols S, Flores-Méndez JA, Piqueras-Olmeda RM, Ochoa-Santiago YM, Albertz-Arévalo N.

Hospital La Fe,
Valencia, Spain;
Email:juandelgadomoraleda@gmail.com
Patient

62 years, female

Categories
Area of Interest Abdomen, Gastrointestinal tract, Pancreas ; Imaging Technique CT
Clinical History
62-year-old woman who complained of epigastric and left upper quadrant pain radiating to the back. On examination, there was jaundice of skin and mucous membranes. Blood tests showed elevated acute phase reactants, total bilirubin, transaminases, alkaline phosphatase, lactate dehydrogenase and amylase.
Imaging Findings
Initial CT shows multiple acute necrotic collections (ANCs), affecting retroperitoneal spaces: left anterior pararenal space, with upper extension to subphrenic space and lower extension until iliac fossa, affecting left paracolic gutter, posterior pararenal space and left psoas muscle. There was also involvement of mesenteric fat.

It’s worthy of mention that in spite of the extension of the collections, the pancreatic gland was not affected.

CT was repeated four weeks later. There were enhancing walls of these collections after intravenous contrast administration, which is indicative of walled-off necrosis (WON).

For treatment, three drainage tubes (28F) were placed because of the high density and abundant detritus of the collections. One of them was placed in the left anterior pararenal space. The other two were placed in the left paracolic gutter.

Incidentally, the patient had a L4-L5 lumbar orthosis for anterolisthesis and extensive bilateral pleural effusion, which produced overlying pulmonary atelectasis.
Discussion
Acute pancreatitis is often diagnosed in emergency radiology services. It is important to properly characterize it because of the clinical consequences for the patient. In 2012 the new classification of Atlanta was made [1]. We are using it in the explanation of this case.

We can differentiate two types of pancreatitis [2]: oedematous or interstitial and necrotizing pancreatitis.

Oedematous pancreatitis is the most common. It is characterized by a diffuse enlargement of the pancreatic gland due to inflammatory oedema. Some inflammation of peripancreatic fat and adjacent fluid collections can be seen.

Necrotizing pancreatitis can show pancreatic necrosis alone (the most uncommon type), necrosis of only the peripancreatic tissues (as this case) or both (most frequent). All its variants have a worse prognosis than oedematous pancreatitis.

Necrotic pancreatic gland is characterized by unenhancing tissue and heterogeneous density.

Peripancreatic collections seen in necrotizing pancreatitis of less than 4 weeks of evolution are called acute necrotic collections (ANCs), as this patient presented in the first CT. 4 weeks later, this collections become walled-off necrosis (WON), as seen in the second scan.

Therefore, the patient presents acute necrotizing pancreatitis with extrapancreatic involvement, sparing the pancreatic gland.

Characterization of necrotizing pancreatitis is a very important issue. Necrotizing pancreatitis involving only the peripancreatic tissue presents better prognosis than pancreatitis with affected parenchyma [3]. However, this kind of pancreatitis is frequently underdiagnosed because it’s frequently confused with oedematous pancreatitis with peripancreatic fluid collections.
Differential Diagnosis List
Necrotizing acute pancreatitis with peripancreatic necrosis alone.
Necrotizing pancreatitis
Interstitial pancreatitis
Spontaneous bacterial peritonitis
Final Diagnosis
Necrotizing acute pancreatitis with peripancreatic necrosis alone.
Case information
URL: https://eurorad.org/case/13676
DOI: 10.1594/EURORAD/CASE.13676
ISSN: 1563-4086
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