acute pancreatic pseudocysts are amylase - rich , fluid - filled cavities surrounded by a wall of inflammatory or fibrous tissue , typically arising 4 weeks after an episode of acute pancreatitis . the incidence of acute pancreatic pseudocysts is reported to be 5 - 15% . complications of severe acute pancreatitis and untreated pancreatic pseudocysts occur infrequently , but with a wide spectrum that includes localized ileus , mechanical obstruction , abscess formation , rupture and perforation into the gastrointestinal tract , and fistula formation . there have been several published case reports and series highlighting the diagnostic and management dilemmas associated with perforations into the colon associated with pseudocysts . the etiology of this condition has remained undetermined , although there are several proposed theories . we report an unusual case of pseudocysts complicating acute pancreatitis presenting with colonic perforation in a patient with a history of chronic mesenteric ischemia . a 71-year - old man with a long history of alcohol abuse , chronic mesenteric ischemia ( celiac and superior mesenteric artery stenosis ) status post celiac artery stent placement 17 months prior , was admitted to the hospital with a 1-month history of epigastric pain , anorexia , and 20 lb weight loss . he also had been having worsening postprandial nausea , vomiting and nonbloody diarrhea . on examination he was febrile and tachycardic ( heart rate was 102 beats per minute and regular ) . pertinent laboratory values were as follows : hemoglobin 7.8 g / dl ; wbc 22,500 cells / mm ( neutrophils 90.7% ) ; ast 151 iu / l ; alt 81 iu / l ; alkaline phosphatase 180 iu / l ; total bilirubin 0.5 mg / dl ; serum amylase 327 u / l ; serum lipase 140 u / l ; and serum lactate 2.20 mmol / l . computerized axial tomography ( cat ) scan of the abdomen confirmed acute pancreatitis with multiple peripancreatic pseudocysts , the largest one adjacent to the pancreatic tail measuring 10.5 cm in diameter ( thus , a giant pseudocyst ) . interestingly , the pseudocysts were also noted to surround the colon near the splenic flexure ( fig . 1 ) . the celiac artery stent appeared patent and the proximal superior mesenteric artery occlusion was noted to be stable and there was refilling of the more distal superior mesenteric artery by collaterals . a subsequent magnetic resonance cholangiopancreatography ( mrcp ) was obtained to further investigate the complex pseudocysts , and this revealed the largest pseudocyst abutting the colon at the splenic flexure . at this location the colon wall appeared thickened with an interval development of air within the giant pseudocyst . 3 ) . therapeutic and diagnostic computed tomography ( ct ) guided percutaneous drainage of the giant pseudocyst was performed . thick purulent fluid was drained and analysis revealed amylase activity of 119,000 u / l . his condition gradually improved with conservative supportive management and further observation in the intensive care unit . follow - up cat scan in week 2 revealed a marked decrease in the size of the giant pseudocyst and absence of free intraperitoneal air . his average daily drainage from the giant pseudocyst was down to 15 ml / day from an initial average of 60 ml / day . he was clinically stable for discharge to a skilled nursing facility after a 2.5-week hospital stay . a recent analysis of pooled data reports the incidence of colonic complications from acute pancreatitis and severe acute pancreatitis as 3.3 and 15% , respectively . because knowledge about colon perforation from acute pancreatic pseudocysts exists mainly from case reports , diagnostic and management dilemmas still persist . table 1 summarizes a review of published cases of acute pancreatic pseudocysts complicated by colon perforation . the natural history of pancreatic pseudocysts varies depending on the cause and severity of the antecedent acute pancreatitis , and also the number , size and location of the pseudocysts [ 2 , 11 , 12 , 13 , 14 ] . although the exact pathogenesis by which pancreatic pseudocysts rupture into the colon is unknown , there have been several proposed theories [ 4 , 5 , 6 , 9 , 10 , 15 ] . first , perforation at the splenic flexure of the colon resulted from pressure exerted by the giant pseudocyst given its close proximity to the bowel . second , acute mesenteric ischemia and/or acute insult to chronic mesenteric ischemia from intravascular volume depletion caused by severe acute pancreatitis possibly contributed to acute colonic infarction and subsequent perforation . aldridge et al .   in reporting their experience on colonic complications of severe acute pancreatitis revealed some similar proposed mechanisms of damage to the colon . they suggested that colonic perforation occurs more commonly at the splenic flexure - a water shed area of the colon which closely abuts the pancreatic tail . also , the authors proposed that direct enzyme activity from the dispersion of pancreatic pseudocyst fluid leads to colon inflammation and necrosis . lastly , they indicated that inflammation and necrosis of the colon may also result from thrombosis of mesenteric and submucosal vessels . this hypothesis according to the authors is based on the presumption that inflammation and edema in the transverse mesocolon when worsened by systemic hypotension precipitates thrombosis which then leads to the retardation of blood flow in the mesenteric vessels . the management of colonic complications of severe acute pancreatitis relies on a high index of suspicion because the clinical presentation is varied , nonspecific , and could occur quite late in the disease process . because such cases mainly have been reported as case reports and series the presentation of the patient as well as the site and severity of the colonic involvement determine whether the utilization of conservative measures such as drainage of the pseudocyst will suffice . although surgical intervention with colon resection may be difficult and complicated , it remains the choice of treatment when perforation or nonviability of the colon is determined . we report a rare case of severe acute pancreatitis with pseudocysts complicated by colon perforation in a patient with a history of chronic mesenteric ischemia . pressure effects from a giant pseudocyst and intravascular volume depletion with acute insult on chronic mesenteric ischemia are possible etiologic factors .
colonic complications of severe acute pancreatitis occur rarely . 
 although there have been several theories on how pancreatic pseudocysts rupture into the colon , the exact pathogenesis remains unknown . 
 we report an unusual case of pseudocysts complicating severe acute pancreatitis presenting with colonic perforation in a 71-year - old man with a history of chronic mesenteric ischemia . 
 pressure effects from a giant pseudocyst and intravascular volume depletion with acute insult on chronic mesenteric ischemia are highlighted as possible etiologic factors .