review of literature on clinical pancreatology - The Pancreapedia

evaluation. The purpose <strong>of</strong> these diagnostic tests is to distinguish benign from malignantcysts <strong>of</strong> the pancreas. Accordingly, it is imperative to distinguish pancreatic pseudocystsfrom their mimics. In one study, the authors explored the cytomorphologic features <strong>of</strong>pseudocyst <strong>of</strong> the pancreas and evaluated the role <strong>of</strong> Alcian blue and mucicarmine stains inthe cytologic evaluation <strong>of</strong> pancreatic cysts. Forty-two patients were identified who had aneventual diagnosis <strong>of</strong> pancreatic pseudocyst and had an endoscopic ultrasound-guided fineneedleaspirate available. Clinical and imaging findings and chemical analyses <strong>of</strong> cyst fluidwere recorded. The cytologic preparations were evaluated for gastrointestinal contamination,inflammatory cells, mucin, and pigmented material. The cytomorphologic features <strong>of</strong> 110neoplastic mucinous cysts (intraductal papillary-mucinous neoplasms/mucinous cysticneoplasms <strong>of</strong> the pancreas) were evaluated and compared with the pseudocysts. Themajority <strong>of</strong> patients (95 %) had a prior episode <strong>of</strong> pancreatitis. On imaging, the pseudocystswere unilocular (92 %). In 69 percent <strong>of</strong> cases, the endosonographic diagnosis was that <strong>of</strong> apseudocyst. The mean carcinoembryonic antigen level was 41 ng/mL. In contrast, thecytopathologist rendered a definitive diagnosis <strong>of</strong> pseudocyst in only 10 percent <strong>of</strong> cases.The majority <strong>of</strong> smears (75 %) revealed neutrophils and/or histiocytes. Atypical epithelialclusters were identified in 3 cases, 1 <strong>of</strong> which was diagnosed as suspicious for carcinoma.Yellow pigmented material, which was identified in 13 pseudocysts (31 %), was not observedin neoplastic mucinous cysts. Alcian blue- and mucicarmine-positive material was identifiedin 64 and 40 percent <strong>of</strong> pseudocysts, respectively, and in 57 and 38 percent <strong>of</strong> neoplasticmucinous cysts, respectively. It was concluded that the cytologic features frequently werenonspecific. The presence <strong>of</strong> yellow pigmented material served as a surrogate marker <strong>of</strong> apseudocyst. Special stains for mucin did not distinguish pseudocysts from neoplasticmucinous cysts [644].To retrospectively evaluate the sensitivity and specificity <strong>of</strong> several morphologic findings thatmay be seen with cystic pancreatic lesions, in the diagnosis <strong>of</strong> pseudocyst at magneticresonance (MR) imaging from 2005 to 2007, electronic radiology and pathology databaseswere searched to identify patients with pancreatic cystic neoplasms or pseudocysts whounderwent pancreatic MR imaging. Twenty-two patients with cystic pancreatic neoplasmsthat were confirmed at surgical resection (n=12) or endoscopic ultrasonography with cysticfluid analysis (n=10) were identified. Of 20 patients with pancreatic pseudocysts, seven hadpseudocysts that were identified at pathologic resection and 13 had a clinical history <strong>of</strong>pancreatitis, with initial computed tomography revealing no pancreatic cyst and subsequentfollow-up MR imaging depicting cystic lesions. Two abdominal radiologists independently andrandomly evaluated each case for presence or absence <strong>of</strong> septa and internal dependentdebris and for external cyst morphology on axial and coronal T2-weighted images and threedimensionalgradient-echo T1-weighted images obtained before and after intravenouscontrast agent administration. Logistic regression for correlated data was used to assess theusefulness <strong>of</strong> internal debris, external morphology, and septa for differentiating cysticneoplasms from pseudocysts. The readers' assessments <strong>of</strong> the presence or absence <strong>of</strong>cystic debris were concordant for 40 (95 %) <strong>of</strong> the 42 patients, with a kappa coefficient <strong>of</strong>0.889, which indicated nearly perfect agreement. Thirteen (93 %) <strong>of</strong> 14 lesions found to havedebris by either or both readers were pseudocysts, and only one (4 %) <strong>of</strong> the 22 cysticneoplasms had debris. Both readers were more likely to identify septa within cysticneoplasms than within pseudocysts; however, the difference was not significant for eitherreader. The readers were more likely to observe microlobulated morphology in cysticneoplasms than in pseudocysts, with the difference between these lesion types, in terms <strong>of</strong>prevalence <strong>of</strong> microlobulated morphology, exhibiting a trend toward-but not reachingstatisticalsignificance. It was concluded that the presence <strong>of</strong> internal dependent debrisappears to be a highly specific MR finding for the diagnosis <strong>of</strong> pancreatic pseudocyst [645].EUSEndoscopic ultrasound (EUS) is useful for the treatment <strong>of</strong> sterile pancreatic fluid collections(PFC), either by means <strong>of</strong> transmural drainage or by complete aspiration. The aim <strong>of</strong> one