Walled-off pancreatic necrosis
Updates to Article Attributes
Walled-off pancreatic necrosis (WOPN) is a late complication of acute pancreatitis, although it can occur in chronic pancreatitis or as a result of pancreatic trauma. Differentiation of WOPN from pancreatic pseudocyst is essential because management differs. WOPN may need aggressive treatment to avoid complications.
Terminology
Walled-off pancreatic necrosis (WOPN) has also been referred to as "walled-off" necrosis (WON). It is different from pancreatic abscess, a term which is no longer used.
Some use the term "walled off pancreatic fluid collections" to include both WOPN and pseudocysts.
Recent changes in classification (2013 Atlanta classification) have recharacterized many lesions that used to be termed "pseudocyst" into "WOPN". Older literature on treatment of "pancreatic pseudocyst" may be cautiously extended into the new WOPN classification.
WOPN usually occurs 4 weeks four weeks after the episode of acute pancreatitis. Before this time, it is referred to as an "acuteacute necrotic collection" (ANC).
Terminology
The following are the latest terms according to the updated Atlanta classification to describe fluid collections associated with acute pancreatitis 10,11:
-
fluid collections associated with interstitial oedematous pancreatitis (i.e. minimal or no necrosis)
- acute peripancreatic fluid collections (APFC): in the first 4 weeks: non-encapsulated peripancreatic fluid collections
- pseudocysts: develop after 4 weeks; encapsulated peripancreatic or remote fluid collections
-
fluid collections associated with necrotising pancreatitis
- acute necrotic collections (ANCs): in the first 4 weeks; non-encapsulated heterogeneous non-liquefied material
- walled-off necrosis (WON or WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material
Clinical presentation
The walled off collection may cause mass effect (e.g. against the biliary system, causing upstream dilatation). It may also become infected.
Pathology
WOPN consists of necrosis and subsequent liquefaction of pancreatic and/or peripancreatic tissue. It may be intrapancreatic or parapancreatic.
Radiologic features
A history of pancreatitis is necessary to exclude a complex cystic neoplasm. One should remember than an obstructing adenocarcinoma can cause pancreatitis, and if this is a concern, follow-up imaging (3-6 months) after the resolution of the pancreatitis would be useful to exclude a mass.
CT
- cystic lesion within or around the pancreas with an area of heterogeneous attenuation nonenhancing (necrotic) tissue, surrounded by a wall 3
- remember to look for other sequelae of pancreatitis (e.g. pseudoaneurysm)
MRI
MRI is superior to CT in differentiating WOPN from pseudocyst, given its ability to depict the internal necrotic debris that favors the WOPN.
Treatment and prognosis
The mortality rate with WOPN is high but less than infected pancreatic necrosis (pancreatic abscess). Management depends on the patient's symptoms and the location of the WOPN. Since 40% of walled-off pancreatic fluid collections (including pseudocysts) resolve spontaneously 4, and ~10% of patients develop complications, conservative treatment may appropriate in some asymptomatic patients 5.
Symptomatic patients should have their WOPN(s) drainedWOPNs drained. Percutaneous catheter drainage and endoscopic retrograde cholangiopancreatography (ERCP) drainage (+/- necrosectomy) have been used to treat the walled off necrosis. These techniques are replacing surgical drainage 1,2.
Because the necrotic debris, WOPN usually requires a wide-bore drainage catheter as compared to the small caliber catheters that can be used to drain a pseudocyst 3.
History and etymology
The term "walled-off pancreatic necrosis" was used by Connor et al in 2005 2.
Differential diagnosis
-<p><strong>Walled-off pancreatic necrosis (WOPN)</strong> is a late complication of <a href="/articles/acute-pancreatitis">acute pancreatitis</a>, although it can occur in <a href="/articles/chronic-pancreatitis">chronic pancreatitis</a> or as a result of <a href="/articles/pancreatic-trauma-1">pancreatic trauma</a>. Differentiation of WOPN from <a href="/articles/pancreatic-pseudocyst-1">pancreatic pseudocyst</a> is essential because management differs. WOPN may need aggressive treatment to avoid complications. </p><h4>Terminology</h4><p><strong>Walled-off pancreatic necrosis (WOPN) </strong>has also been referred to as "walled-off" necrosis (WON). It is different from <a href="/articles/pancreatic-abscess">pancreatic abscess</a>, a term which is no longer used.</p><p>Some use the term "walled off pancreatic fluid collections" to include both WOPN and pseudocysts.</p><p>Recent changes in classification (2013 <a href="/articles/international-multidisciplinary-classification-of-acute-pancreatitis-severity">Atlanta classification</a>) have recharacterized many lesions that used to be termed "pseudocyst" into "WOPN". Older literature on treatment of "pancreatic pseudocyst" may be cautiously extended into the new WOPN classification.</p><p>WOPN occurs 4 weeks after the episode of acute pancreatitis. Before this time, it is referred to as an "acute necrotic collection" (ANC).</p><h4>Clinical presentation</h4><p>The walled off collection may cause mass effect (e.g. against the biliary system, causing upstream dilatation). It may also become infected.</p><h4>Pathology</h4><p>WOPN consists of necrosis and subsequent liquefaction of pancreatic and/or peripancreatic tissue. It may be intrapancreatic or parapancreatic.</p><h4>Radiologic features</h4><p>A history of pancreatitis is necessary to exclude a complex cystic neoplasm. One should remember than an obstructing adenocarcinoma can cause pancreatitis, and if this is a concern, follow-up imaging (3-6 months) after the resolution of the pancreatitis would be useful to exclude a mass.</p><h5>CT</h5><ul>- +<p><strong>Walled-off pancreatic necrosis (WOPN)</strong> is a late complication of <a href="/articles/acute-pancreatitis">acute pancreatitis</a>, although it can occur in <a href="/articles/chronic-pancreatitis">chronic pancreatitis</a> or as a result of <a href="/articles/pancreatic-trauma-1">pancreatic trauma</a>. Differentiation of WOPN from <a href="/articles/pancreatic-pseudocyst-1">pancreatic pseudocyst</a> is essential because management differs. WOPN may need aggressive treatment to avoid complications. </p><p>WOPN usually occurs four weeks after the episode of acute pancreatitis. Before this time, it is referred to as an <a href="/articles/acute-necrotic-collection">acute necrotic collection</a> (ANC).</p><h4>Terminology</h4><p>The following are the latest terms according to the updated <a href="/articles/international-multidisciplinary-classification-of-acute-pancreatitis-severity">Atlanta classification</a> to describe fluid collections associated with acute pancreatitis <sup>10,11</sup>:</p><ul>
- +<li>fluid collections associated with <a title="Interstitial oedematous pancreatitis" href="/articles/interstitial-oedematous-pancreatitis">interstitial oedematous pancreatitis</a> (i.e. minimal or no necrosis)<ul>
- +<li>
- +<a href="/articles/acute-peripancreatic-fluid-collection">acute peripancreatic fluid collections</a> (APFC): in the first 4 weeks: non-encapsulated peripancreatic fluid collections</li>
- +<li>
- +<a href="/articles/pancreatic-pseudocyst-1">pseudocysts</a>: develop after 4 weeks; encapsulated peripancreatic or remote fluid collections</li>
- +</ul>
- +</li>
- +<li>fluid collections associated with <a href="/articles/necrotising-pancreatitis">necrotising pancreatitis</a><ul>
- +<li>
- +<a href="/articles/missing">acute necrotic collections</a> (ANCs): in the first 4 weeks; non-encapsulated heterogeneous non-liquefied material</li>
- +<li>
- +<a href="/articles/walled-off-pancreatic-necrosis-1">walled-off necrosis</a> (WON or WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material </li>
- +</ul>
- +</li>
- +</ul><h4>Clinical presentation</h4><p>The walled off collection may cause mass effect (e.g. against the biliary system, causing upstream dilatation). It may also become infected.</p><h4>Pathology</h4><p>WOPN consists of necrosis and subsequent liquefaction of pancreatic and/or peripancreatic tissue. It may be intrapancreatic or parapancreatic.</p><h4>Radiologic features</h4><p>A history of pancreatitis is necessary to exclude a complex cystic neoplasm. One should remember than an obstructing adenocarcinoma can cause pancreatitis, and if this is a concern, follow-up imaging (3-6 months) after the resolution of the pancreatitis would be useful to exclude a mass.</p><h5>CT</h5><ul>
-<li>remember to look for other sequelae of pancreatitis (e.g. pseudoaneurysm)</li>-</ul><h5>MRI</h5><p>MRI is superior to CT in differentiating WOPN from pseudocyst, given its ability to depict the internal necrotic debris that favors the WOPN.</p><h4>Treatment and prognosis</h4><p>The mortality rate with WOPN is high but less than infected pancreatic necrosis (pancreatic abscess). Management depends on the patient's symptoms and the location of the WOPN. Since 40% of walled-off pancreatic fluid collections (including pseudocysts) resolve spontaneously <sup>4</sup>, and ~10% of patients develop complications, conservative treatment may appropriate in some asymptomatic patients <sup>5</sup>.</p><p>Symptomatic patients should have their WOPN(s) drained. Percutaneous catheter drainage and endoscopic retrograde cholangiopancreatography (ERCP) drainage (+/- necrosectomy) have been used to treat the walled off necrosis. These techniques are replacing surgical drainage <sup>1,2</sup>.</p><p>Because the necrotic debris, WOPN usually requires a wide-bore drainage catheter as compared to the small caliber catheters that can be used to drain a pseudocyst <sup>3</sup>.</p><h4>History and etymology</h4><p>The term "walled-off pancreatic necrosis" was used by <strong>Connor </strong>et al in 2005 <sup>2</sup>.</p><h4>Differential diagnosis</h4><ul>- +<li>remember to look for other sequelae of pancreatitis (e.g. <a href="/articles/false-aneurysm">pseudoaneurysm</a>)</li>
- +</ul><h5>MRI</h5><p>MRI is superior to CT in differentiating WOPN from pseudocyst, given its ability to depict the internal necrotic debris that favors the WOPN.</p><h4>Treatment and prognosis</h4><p>The mortality rate with WOPN is high but less than infected pancreatic necrosis (pancreatic abscess). Management depends on the patient's symptoms and the location of the WOPN. Since 40% of walled-off pancreatic fluid collections (including pseudocysts) resolve spontaneously <sup>4</sup>, and ~10% of patients develop complications, conservative treatment may appropriate in some asymptomatic patients <sup>5</sup>.</p><p>Symptomatic patients should have WOPNs drained. Percutaneous catheter drainage and endoscopic retrograde cholangiopancreatography (ERCP) drainage (+/- necrosectomy) have been used to treat the walled off necrosis. These techniques are replacing surgical drainage <sup>1,2</sup>.</p><p>Because the necrotic debris, WOPN usually requires a wide-bore drainage catheter as compared to the small caliber catheters that can be used to drain a pseudocyst <sup>3</sup>.</p><h4>History and etymology</h4><p>The term "walled-off pancreatic necrosis" was used by <strong>Connor </strong>et al in 2005 <sup>2</sup>.</p><h4>Differential diagnosis</h4><ul>
Image 1 CT (C+ portal venous phase) ( update )
Image 2 CT (C+ portal venous phase) ( update )
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