LAUSR

To the Editor: We read with keen interest the paper by Koutroumpakis et al1 regarding the clinical significance of isolated peripancreatic necrosis (PPN). The authors need to be congratulated for evaluating PPN extensively in a prospective cohort of 400 patients with acute pancreatitis. We had also previously reported the clinical significance of extrapancreatic necrosis (EPN) alone in 213 patients with acute pancreatitis and found that EPN alone has a less severe course compared with pancreatic necrosis (PN) but a more severe course compared with interstitial pancreatitis.2 We believe that the term EPN may be more apt to describe this phenomenon as necrosis may extend to distant areas and may not be confined to the peripancreatic tissues. Also, many previous reports have used the term EPN to describe this process.2–4 We found EPN in 25% of our patients, and this frequency is higher than the frequency reported in the current study (11%). This difference is probably due to the varying definitions of EPN used in these studies. In concurrence with the current study, we also found that, when compared with patients with PN, patients with EPN alone had a similar frequency of organ failure as well as mortality. As tissue injury is a triggering event for inflammatory cascade that leads to organ failure and as this is common to both PN and EPN, we believe that this could be the reason for the similar frequency of organ failure in both groups. Moreover, as reported by the authors, we also found that significantly more number of patients with PN required intervention as compared with patients with EPN alone (33% vs. 15%, respectively; P=0.016). The authors also classified PPN as limited and extensive, depending upon the size and number of locations.1 Previously, we have also classified EPN as limited and extensive depending upon the extent of involvement. We described extensive EPN as EPN that involved pelvis or paracolic gutters and also documented that this may be associated with an increased frequency of pleural effusions, ascites, and multiorgan failure.2,3 The authors report the comparison between limited and extensive only among patients having EPN alone, whereas in our report we had included the entire group of patients with necrotizing pancreatitis and compared them with patients with limited and extensive EPN. Pooling of data from multiple reports suggests that the mortality from EPN alone is intermediate to the interstitial and necrotizing pancreatitis groups.3 The results in the current study are important as they add to the growing evidence that as an entity EPN alone may represent a subgroup that is distinctive from the interstitial and parenchymal necrosis group with outcomes that are somewhere between the other 2 groups.2 Also, the presence of extensive EPN may further distinguish the subgroup of patients who may have a guarded prognosis.