Intraductal papillary mucinous neoplasm of the pancreas: can benign lesions be differentiated from malignant lesions with multidetector CT?

Macrocystic pancreatic lesions: differentiation of benign from premalignant and malignant cysts by CT

OBJECTIVE

To assess useful CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions.

METHODS

Seventy-four patients with pathologically proven macrocystic pancreatic lesions were enrolled: 17 benign cysts (macrocystic serous cystadenoma, n=12; congenital cyst; n=5) and 57 premalignant and malignant cysts (mucinous cystic neoplasm, n=28; intraductal papillary mucinous neoplasm of branch duct type, n=20; tumor with cystic change, n=9). Size, location, shape (lobulated, round or oval, or complex cystic with tubular cyst), wall thickness (thin, < or =1mm; thick, >1mm), internal surface (smooth or irregular), and other findings were analyzed with multiphasic CT with thin-section (2.5-3mm) images. CT features between two groups were compared using univariate and multivariate stepwise logistic regression analyses.

RESULTS

On univariate analysis, the differences for the shape (p=0.007), wall thickness (p=0.011), and internal surface (p=0.012) between benign and premalignant and malignant cysts were significant. A lobulated shape, a thin wall and a smooth internal surface were more frequent in benign cysts, whereas a round or oval shape or a complex cystic shape with tubular cyst, a thick wall and an irregular internal surface were more frequent in premalignant and malignant cysts. On multivariate analysis, the shape (p=0.002) and wall thickness (p=0.025) were significant CT features for differentiating benign from premalignant and malignant cysts.

CONCLUSION

Shape and wall thickness are the main CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions.

Laparoscopic vs. open resection of noninvasive intraductal pancreatic mucinous neoplasms

Required resection margins for noninvasive intraductal papillary mucinous neoplasms (IPMNs) are a controversial issue. Over a 10-year period we have resected IPMNs from the entire pancreatic gland with minimally invasive techniques and compared our survival and complication rates with open controls to see if any difference in resection margins and outcomes could be observed. Data were collected retrospectively, including our first cases of advanced laparoscopic resections. Five-year Kaplan-Meier curves were calculated and statistical analysis was performed using the log rank and Student's T test for continuous variables. Chi square and Fisher's exact tests were used for analyzing categorical variables. From March 1997 to February 2006, we operated on 22 patients with noninvasive IPMNs, of which 9 (41%) were operated on laparoscopically and 13 (59%) using open techniques. Three patients underwent laparoscopic duodenopancreatectomy, compared to five in the open group. All resection margins were negative, but two patients required total pancreatectomy, both of which were performed laparoscopically. One of these was converted to open (11%) because of difficulty in reconstructing the biliary anastomosis. The overall complication rates were 56% for the laparoscopic group and 85% for the open group. Twenty-two percent of the laparoscopic group required reoperation and 11% required percutaneous drainage, compared to 15 and 23% in the open group, respectively. All patients are alive after a mean of 20 months (range = 2-43) in the laparoscopic group and 37 months (range = 1-121) in the open one (p > 0.05). Laparoscopic resection of noninvasive IPMNs of the entire pancreatic gland has similar complication and survival rates as open procedures. As a result, the laparoscopic approach is appropriate for noninvasive IPMNs of the entire pancreatic gland; however, larger cohorts are needed to see if any approach has superior outcomes. Because of these favorable results, studies are currently underway to see if the minimally invasive approach is also appropriate for invasive IPMNs.

Cystic tumors of the pancreas: ultrasound, computed tomography, and magnetic resonance imaging features

Cystic tumors of the pancreas are a subset of rare pancreatic tumors that vary from benign to malignant. Many have specific imaging findings that allow them to be differentiated from each other. This article aims to review the histopathologic and imaging findings of the relatively common lesions (serous microcystic adenoma, mucinous cystic tumor, intraductal papillary mucinous tumor, and solid pseudopapillary tumor) and uncommon lesions (cystic endocrine tumors, cystic metastases, cystic teratomas, and lymphangiomas) in this group.

An evidence-based review for the management of cystic pancreatic lesions

The incidental finding of pancreatic cysts is becoming more common because of the increased use of cross-sectional imaging. As a result, the perspective from historical series of symptomatic patients is not always applicable to the current cohort of patients with cystic lesions in their pancreas. In this review, the characteristic radiological features that aid diagnosis are highlighted, and the complementary role of different imaging methods and the appropriate use of tissue sampling are identified. Based on the literature regarding the diagnostic role of imaging in characterizing cystic pancreatic lesions, it is possible to recommend a practical imaging algorithm for the diagnosis of cystic pancreatic lesions.

ACG practice guidelines for the diagnosis and management of neoplastic pancreatic cysts

The diagnosis and management of pancreatic cystic lesions is a common problem. At least 1% of hospitalized patients at major medical centers will have a pancreatic cystic lesion on cross sectional imaging. Up to a quarter of all pancreata examined in an autopsy series contained a pancreatic cyst, 16% of which were lined by an "atypical" epithelium and 3% of which had progressed to carcinoma-in-situ (high grade dysplasia). in the past, it was thought these cystic lesions were benign, but increasing evidence points to the cystic lesions as being the origin of some pancreatic malignancies. The most important clinical tools in the diagnosis and management of pancreatic cystic lesions are cross sectional imaging, endoscopic ultrasound, and cyst fluid analysis. The most important differential diagnosis is distinguishing mucinous (pre-malignant) and non-mucinous cystic lesions. The findings of a macrocystic lesion containing viscous fluid rich in CEA are supportive of a diagnosis of a mucinous lesion. Serous lesion are the most common non-mucinous cyst and are characterized by a microcystic morphology, non-viscous fluid and a low concentration of CEA in the cyst fluid. The following document includes a description of neoplastic pancreatic cysts, a critical review of relevant diagnostic tests, and a discussion of treatment options. We have proposed a set of guidelines for the diagnosis and management of patients with neoplastic pancreatic cysts. The guidelines are based on published data backed by an analysis of the quality of the data and are designed to address the most frequent and important clinical scenarios. In addition to providing a summary of the diagnostic data, we offer diagnostic and management suggestions based on 13 common clinical problems. Although the field is rapidly evolving, a set of core principles is provided based on a balance between the risk of malignancy and the benefit of pancreatic resection.

The Spectrum of Cystic Masses of the Pancreas: Imaging Features and Diagnostic Difficulties

Cystic masses of the pancreas comprise a diverse group of pathologic entities ranging from pseudocysts to cystic tumors. Although their presentations may be similar, the appropriate treatment and patient management can differ greatly. There is an overlap in radiologic features, but the clinical context and some imaging findings are useful in differentiating among these entities; the differential diagnosis could be considerably reduced and it is generally possible to reach the correct diagnosis. In this article, we review imaging characteristics and radiologic patterns of both common and uncommon cystic masses of the pancreas. An algorithmic approach for the management of cystic pancreatic lesions is proposed.

Strategies for screening for pancreatic adenocarcinoma in high-risk patients

Identification of high-risk individuals, genetic counseling, and informed consent are important components of a screening program for familial pancreatic cancer. Screening high-risk individuals with imaging tests, such endoscopic ultrasound (EUS) and computed tomography (CT), can lead to the detection and treatment of predominantly asymptomatic early pancreatic neoplasms, as well as extra-pancreatic tumors. These pancreatic neoplasms consist of resectable, mostly branch-type non-invasive intraductal papillary mucinous neoplasms (IPMNs). EUS can visualize these very early IPMNs as focal duct ectasias or cysts. EUS features of chronic pancreatitis are highly prevalent in high-risk individuals and these directly correlate with multifocal lobulocentric parenchymal atrophy due to multifocal pancreatic intraepithelial neoplasia (PanIN). No one molecular marker is ready for "prime time" screening of high-risk individuals. Translational studies are underway to discover novel biomarkers for IPMNs, PanIN-3 lesions, or microinvasive adenocarcinoma, which are likely to be cured by timely intervention. Long-term, multi-prospective studies are needed to determine if screening for early pancreatic neoplasia and timely intervention results in decreased pancreatic cancer incidence and mortality in high-risk individuals.

Intraductal papillary mucinous neoplasia

Intraductal papillary mucinous neoplasia is a neoplastic disorder of varying degree and extent that affects the pancreatic ductal epithelium. Clinical presentations may vary from an asymptomatic incidental finding to obstructive jaundice. Harbingers of malignancy include symptoms of jaundice, weight loss, or new-onset diabetes. In the absence of findings that correlate with malignancy, natural history is unknown. Management of these patients is controversial, and should be individualized based on surgical risk.

Clinical importance of precursor lesions in the pancreas

Three distinct noninvasive precursor lesions to invasive ductal adenocarcinoma of the pancreas have been described. These include the mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, and pancreatic intraepithelial neoplasia. The early detection and treatment of these lesions can interrupt the progression of a curable noninvasive precursor to an almost uniformly deadly invasive cancer.