Extrapancreatic necrotizing pancreatitis with viable pancreas: A previously under-appreciated entity

Background: Necrotizing pancreatitis is generally considered to involve the pancreatic parenchyma in all patients, and, as an extension of the necroti c process, the peripancreatic tissues as well. We identified a subgroup of patients in whom the necrotic process involves apparently extrapancreatic t issues alone (EXPN), as opposed to the usual combined parenchymal and perip ancreatic necrosis (PN). Study Design: The objective of this study was to compare clinical courses o f EXPN and PN. Data were reviewed on 82 consecutive patients with necrotizi ng pancreatitis treated operatively between 1983 and 1997. The extent of pa ncreatic parenchymal necrosis (expressed as percent of pancreas based on co ntrast-enhanced CT and operative findings) was estimated in 62 patients. Di agnosis of EXPN required normal enhancement of entire pancreas on dynamic C T and operative documentation of viability of the gland. Results: Twelve patients (19%) had EXPN and 50 (81%) had PN. Gender, age, b ody mass index, etiology of pancreatitis, prevalence, and type of infection were similar between groups, but APACHE-II scores on admission were less i n EXPN (6+/-2 versus 10+/-1, p = 0.02). Patients with EXPN required fewer r eoperative necrosectomies (0.7 versus 3.2, p = 0.009) and did not develop p ancreatic or gastrointestinal fistulas (0 versus 19 patients) or hemorrhage (0 versus 8 patients). ICU stays were similar, but hospital stays in EXPN were shorter (29 +/- 6 versus 54+/-5 days, p = 0.01) and mortality was less (8% and 20%, p < 0.001). Conclusions: Necrotizing pancreatitis manifesting as EXPN is not rare. EXPN is a less aggressive form of necrotizing pancreatitis, locally and systemi cally, and signifies a better prognosis. (J Am Cell Surg 1999;188: 643-648. (C) 1999 by the American College of Surgeons).