Incidental cystic neoplasms of pancreas: what is the optimal interval of imaging surveillance?

The incidental pancreatic cyst

The discovery of a pancreatic cyst in an asymptomatic patient presents an immediate challenge to the interpreting radiologist, the clinician who manages the patient, and patients themselves. When a cyst is discovered on imaging in a patient without symptoms directly referable to the pancreas, the following questions are immediately raised: can the lesion be accurately diagnosed or is the appropriate management clear from the examination, is the best management approach to suggest watchful waiting with follow-up imaging, what is the best method for imaging follow-up, and what is the optimal frequency of follow-up? This article recommends an approach to analyzing patients with incidental pancreatic cysts.

Management of mucinous cystic neoplasms of the pancreas

The purpose of this study was to investigate the actual management of mucinous cystic neoplasm (MCN) of the pancreas. A systematic review was performed in December 2009 by consulting PubMed MEDLINE for publications and matching the key words “pancreatic mucinous cystic neoplasm”, “pancreatic mucinous cystic tumour”, “pancreatic mucinous cystic mass”, “pancreatic cyst”, and “pancreatic cystic neoplasm” to identify English language articles describing the diagnosis and treatment of the mucinous cystic neoplasm of the pancreas. In total, 16 322 references ranging from January 1969 to December 2009 were analysed and 77 articles were identified. No articles published before 1996 were selected because MCNs were not previously considered to be a completely autonomous disease. Definition, epidemiology, anatomopathological findings, clinical presentation, preoperative evaluation, treatment and prognosis were reviewed. MCNs are pancreatic mucin-producing cysts with a distinctive ovarian-type stroma localized in the body-tail of the gland and occurring in middle-aged females. The majority of MCNs are slow growing and asymptomatic. The prevalence of invasive carcinoma varies between 6% and 55%. Preoperative diagnosis depends on a combination of clinical features, tumor markers, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound with cyst fluid analysis, and positron emission tomography-CT. Surgery is indicated for all MCNs.

Evaluation of cyst fluid CEA analysis in the diagnosis of mucinous cysts of the pancreas

BACKGROUND

Although cyst fluid carcinoembryonic antigen (CEA; > 192 ng/ml) is the preferred test for identifying mucinous pancreatic cysts, the data are more robust for mucinous cystic neoplasms (MCN) than for intraductal papillary mucinous neoplasms (IPMN). The role of cyst fluid CEA as a marker for either malignancy or malignant progression is uncertain.

METHODS

All patients with pancreatic cysts who had undergone endoscopic ultrasound with cyst fluid CEA measurement between 2001 and 2009 were identified. Patient outcomes and pathology from operative resections were recorded.

RESULTS

Two hundred sixty-seven patients were identified; pathological diagnosis was obtained in 97. Mucinous cysts were identified in 66 of 97 (68%): benign IPMN, n = 42; malignant IPMN, n = 10; benign MCN, n = 12; malignant MCN, n = 2. CEA > 192 ng/mL had a sensitivity and specificity of 73% and 65% for identifying mucinous cysts; cyst fluid CEA was not associated with malignancy (p = 0.85). One hundred seventy-eight patients were managed with an initial non-operative strategy. Eight (4%) developed radiographic changes necessitating surgery; pathology demonstrated seven benign mucinous cysts and one retention cyst. CEA was not associated with radiographic progression (p = 0.37).

CONCLUSIONS

Cyst fluid CEA is a useful test for identifying mucinous cysts, including MCN and IPMN. In mucinous cysts, cyst fluid CEA is not associated with malignancy or radiographic progression.

Pancreatic cyst aspiration analysis for cystic neoplasms: mucin or carcinoembryonic antigen--which is better?

BACKGROUND

Differentiation between the various pathologies presenting as a cystic pancreatic lesion is clinically important but often challenging. We have previously advocated the performance of endoscopic ultrasound (EUS) with aspiration and determination of mucin and carcinoembryonic antigen (CEA) content. We sought to report the results of this ongoing protocol and determine the relative importance of cyst fluid mucin and CEA for the diagnostic process.

METHODS

The institutions prospectively maintained pancreatic cyst database was accessed to identify patients who had undergone pancreatic EUS and cyst aspiration as part of their evaluation. Only those patients who had subsequently undergone resection were selected, with histopathology being the gold standard for comparison.

RESULTS

From January 2000 to July 2009, 174 patients with pancreatic cystic disease underwent surgery, 121 of whom had an EUS with aspiration attempted at our institution with specimens sent for mucin and CEA. Based on histopathology, 86 mucinous lesions were identified, including 44 cystadenomas, 34 intraductal papillary mucinous neoplasms, 7 mucinous adenocarcinomas, and 1 intraductal oncocytic papillary neoplasm; 42 were nonmucinous lesions. The median cyst CEA levels were significantly higher in the mucinous lesions group at 850 versus 2 ng/mL (P = .001). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive diagnostic likelihood ratio, and negative diagnostic likelihood ratio (NDLR) were calculated respectively for mucin alone (0.80, 0.40, 0.61, 0.63, 1.33, 0.68); CEA alone (0.93, 0.43, 0.51, 0.91, 1.63, 0.16); cytology alone (0.38, 0.9, 0.92, 0.31, 3.67, 0.69); mucin or CEA (0.83, 0.65, 0.87, 0.57, 2.51, 0.26); mucin or CEA or cytology (0.92, 0.52, 0.86, 0.68, 1.91, 0.15); mucin plus CEA (0.96, 0.34, 0.25, 0.97, 1.45, 0.12); mucin plus cytology (0.25, 0.97, 0.96, 0.29,7.25, 0.78); CEA plus cytology (0.12, 1.00, 1.00, 0.26, ∞, 0.88); and mucin plus CEA plus cytology (0.08, 1.00, 1.00, 0.25, ∞, 0.92).

CONCLUSION

Assessment of cyst mucin and CEA are complementary, with the best profile obtained when both markers are determined along with cytology. This combination provides a good sensitivity, PPV, and NDLR, as well as reasonable PPV and PDNR.

Multidisciplinary management strategy for incidental cystic lesions of the pancreas

BACKGROUND

At our institution, incidental pancreatic cysts are frequently identified in asymptomatic patients undergoing routine imaging for staging of nonpancreatic malignancies. Management of these patients is unclear because a small but significant number of incidental pancreatic cysts are malignant.

STUDY DESIGN

Our institutional database was reviewed for patients with ICD-9 codes for pancreatic cysts from 1980 to 2005. Clinicopathologic factors, including CT and endoscopic ultrasound (EUS) characteristics and management strategies, were analyzed.

RESULTS

Over 25 years, 942 patients were identified with pancreatic cysts. Excluding those with symptoms or pseudocysts, 350 patients remained with incidental pancreatic cysts. Mean overall survival was 41.4 months (mean follow-up 32.7 months). Forty-one patients underwent resection, of whom 38 (92.7%) had premalignant or malignant pathology. Univariate analysis of variables predicting pathologic premalignant or malignant diagnosis identified pancreatic neck or body location as significant factors.

CONCLUSIONS

These data suggest that most incidental pancreatic cysts can be managed nonoperatively using a selective strategy based on detailed review of CT imaging and EUS findings.

Incidental pancreatic cysts: do we really know what we are watching?

BACKGROUND

Most cystic neoplasms of the pancreas (CNPs) are incidentally discovered. Their management continues to be debated and preoperative diagnosis is often inaccurate.

METHODS

Retrospective review of 330 patients with incidentally discovered CNPs. Preoperative and final histological diagnoses were correlated.

RESULTS

41% (136/330) of patients were operated on at diagnosis. 50 patients underwent resection for a presumed branch-duct (Bd) intraductal papillary mucinous neoplasm (IPMN), which was confirmed in only 64% (32/50); of the remaining patients, 20% had main-duct involvement. Mucinous cystic neoplasm was the preoperative diagnosis in 30/136 patients, histologic examination was confirmatory in only 60% (18/30). Most lesions presumed to be main-duct or combined IPMNs or serous cystadenomas were confirmed as such after resection (15/16 and 11/12, respectively). Multifocality was not only associated with Bd-IPMN, and 5% of all cysts were non-neoplastic. Overall, in only 68% of cases did the preoperative and histological diagnoses match.

CONCLUSIONS

In an experienced, high-volume center, preoperative diagnosis was incorrect in one-third of incidentally discovered CNPs who underwent resection. Of particular concern, 20% of presumed Bd-IPMN had a main-duct component. Conversely, 5% of resected cysts were not even neoplastic. Clearly, better diagnostic methods are needed to aid in formulating appropriate treatment strategies.

Differentiating pancreatic cystic neoplasms from pancreatic pseudocysts at MR imaging: value of perceived internal debris

PURPOSE

To retrospectively evaluate the sensitivity and specificity of several morphologic findings that may be seen with cystic pancreatic lesions, in the diagnosis of pseudocyst at magnetic resonance (MR) imaging.

MATERIALS AND METHODS

This study was institutional review board approved and HIPAA compliant. From January 1, 2005, to December 31, 2007, electronic radiology and pathology databases were searched to identify patients with pancreatic cystic neoplasms or pseudocysts who underwent pancreatic MR imaging. Twenty-two patients with cystic pancreatic neoplasms that were confirmed at surgical resection (n = 12) or endoscopic ultrasonography (US) with cystic fluid analysis (n = 10) were identified. Of 20 patients with pancreatic pseudocysts, seven had pseudocysts that were identified at pathologic resection and 13 had a clinical history of pancreatitis, with initial computed tomography (CT) revealing no pancreatic cyst and subsequent follow-up MR imaging depicting cystic lesions. Two abdominal radiologists independently and randomly evaluated each case for presence or absence of septa and internal dependent debris and for external cyst morphology on axial and coronal T2-weighted images and three-dimensional gradient-echo T1-weighted images obtained before and after intravenous contrast agent administration. Logistic regression for correlated data was used to assess the usefulness of internal debris, external morphology, and septa for differentiating cystic neoplasms from pseudocysts.

RESULTS

The readers' assessments of the presence or absence of cystic debris were concordant for 40 (95%) of the 42 patients, with a kappa coefficient of 0.889, which indicated nearly perfect agreement. Thirteen (93%) of 14 lesions found to have debris by either or both readers were pseudocysts, and only one (4%) of the 22 cystic neoplasms had debris. Both readers were more likely to identify septa within cystic neoplasms than within pseudocysts; however, the difference was not significant for either reader. The readers were more likely to observe microlobulated morphology in cystic neoplasms than in pseudocysts, with the difference between these lesion types, in terms of prevalence of microlobulated morphology, exhibiting a trend toward-but not reaching-statistical significance (P = .0627).

CONCLUSION

Presence of internal dependent debris appears to be a highly specific MR finding for the diagnosis of pancreatic pseudocyst.