Mucinous cystic neoplasms of the pancreas with ovarian stroma

Reducing the burden of pancreatic cancer by surveilling mucinous cystic neoplasms: are we there yet?

Pancreatic cystic neoplasms are a common condition, with intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) being of particular concern due to their potential for malignant transformation. Resection of these lesions before progression to invasive cancer represents a crucial opportunity to reduce the burden of pancreatic cancer. However, the benefit of early-resection must be weighed against the risk of overtreatment. Applying current guidelines, nearly half of the patients who undergo resection for IPMN might not have required surgery, while malignancy is detected in only 16 % of resected MCNs. This raises concerns, particularly given the increasing detection of small cysts with the widespread use of radiological imaging and the significant postoperative risks, including exocrine and endocrine insufficiency. Emerging evidence suggests that surveillance strategies could be more broadly applied, reducing unnecessary surgeries. This review aims to reassess the current evidence regarding both surgical resection and surveillance of IPMNs and MCNs.

Feasibility of Surveillance for Mucinous Cystic Neoplasm of the Pancreas: A Multi-Institutional Retrospective Study of 328 Patients by the Japanese Pancreatic Society

OBJECTIVE

We aimed to elucidate the feasibility of surveillance of patients with mucinous cystic neoplasm (MCN).

METHODS

We performed a retrospective, multi-institutional study of 328 patients who underwent surgery for MCN at 18 Japanese institutions. Patients with MCN were divided into an immediate surgery group and a surveillance group, which underwent surgery after surveillance.

RESULTS

The median surveillance period until surgery in the surveillance group was 27 months (range, 7-165 months). Compared with the immediate surgery group, the surveillance group showed smaller tumor diameter (46 vs 50 mm, P = 0.01), more frequent laparoscopic approach (58% vs 37%, P < 0.01), and less frequent malignancy (7% vs 15%, P = 0.03). The new appearance of mural nodules and elevation of serum tumor markers were associated with malignancy in the surveillance group. Two patients in the surveillance group experienced postoperative recurrence, although there was no significant difference in recurrence or disease-free survival between the two groups. In the surveillance group, the 1-, 5-, and 10-year cumulative incidence rates of malignant MCN were 0.8%, 5.6%, and 36.5%, respectively.

CONCLUSION

As the risk of progression to malignant MCNs increases over the long term, MCNs should be resected rather than subjected to unnecessary surveillance.

Huge mucinous cystic neoplasms with adhesion to the left colon: A case report and literature review

Mucinous cystic neoplasms (MCN) are rare premalignant neoplasms of the pancreas typically found as single lesions in the pancreatic body and tail of women in the fifth and sixth decade of life, constituting 2-5% of pancreatic neoplasms. We present a 50-year-old female patient with a large tail mass of the pancreatic body (size of 15 cm × 12 cm) with elevated tumor indicators. Computed tomography and magnetic resonance imaging revealed a large cystic lesion with septa and wall nodules. During the operation, the tumor capsule wall adhered to the left half colon and mesentery and could not be detached. Splenectomy and left hemicolectomy were performed. The postoperative pathological examination of the specimens confirmed a premalignant pancreatic mucous cystic tumor with moderate heterocytosis. The preoperative diagnosis of pancreatic MCN and MCN with invasive carcinoma is discussed, considering the characteristics of this case. Age, tumor size, texture, tumor marker elevation, and cystic wall condition are important characteristics of malignant MCN. Nevertheless, it is still very difficult to determine accurately whether an MCN is malignant or not before an actual pathological examination of the resected specimen.

Integrating Molecular Analysis into the Pathologic Evaluation of Pancreatic Cysts

The development of cross-sectional imaging techniques has enhanced the detection of pancreatic cystic lesions (PCLs). PCLs are found in approximately 2% of the general population, often as incidentally detected lesions on computed tomography or MRI during the evaluation of other medical conditions. Broadly, PCLs are classified as mucinous or nonmucinous. Mucinous PCLs include mucinous cystic neoplasms and intraductal papillary mucinous neoplasms. Nonmucinous PCLs include pseudocysts, serous cystadenomas, solid pseudopapillary neoplasms, and cystic pancreatic neuroendocrine tumors, as well as cystic acinar cell carcinoma, cystic degeneration of pancreatic ductal adenocarcinoma, lymphoepithelial cyst, and others.

State-of-the-Art Update of Pancreatic Cysts

Andrew Canakis.

Pancreatic mucinous cystic neoplasms located in the distal pancreas: a multicenter study

BACKGROUND

Mucinous cysts of the pancreas (MCN) are infrequent, usually unilocular tumors which occur in postmenopausal women and are located in the pancreatic body/tail. The risk of malignancy is low. The objective is to define preoperative risk factors of malignancy in pancreatic MCN and to assess the feasibility of the laparoscopic approach.

METHODS

Retrospective multicenter observational study of prospectively recorded data regarding distal pancreatectomies was carried out at seven hepatopancreatobiliary (HPB) Units between 01/01/08 and 31/12/18 (the ERPANDIS Project).

RESULTS

Four hundred and forty-four distal pancreatectomies were recorded including 47 MCN (10.6%). Thirty-five were non-invasive tumors (74.5%). In all, 93% of patients were female, and 60% were ASA (American Society of Anaesthesiology) II. The mean preoperative size was 46 mm. Patients with invasive tumors were older (54 vs. 63 years). Invasive tumors were larger (6 vs. 4 cm), although the difference was not significant (P=0.287). Sixty percent was operated via laparoscopic approach, which was used in 74.6% of non-invasive tumors and in 16.7% of the invasive ones. The spleen was not preserved in 93.6% of the patients. R0 resection was obtained in all patients. Two patients with invasive tumors died.

CONCLUSIONS

In our surgical series of MCN, patients with malignancy were older and presented larger tumors, although the difference was not statistically significant. Laparoscopy is a safe and feasible approach for MCN. Prospective studies are now needed to define risk factors that can guide the decision whether to administer conservative treatment or to operate.

Actual malignancy risk of either operated or non-operated presumed mucinous cystic neoplasms of the pancreas under surveillance

BACKGROUND

Despite the low malignant potential of pancreatic mucinous cystic neoplasms (MCNs), surgery is still performed. The aim of this pragmatic study was to assess the outcome of surgery and surveillance for patients presenting with a presumed MCN at the first evaluation.

METHODS

Data for patients with a presumed MCN observed from 2000 to 2016 at the Verona Pancreas Institute and San Raffaele Hospital were extracted from prospective databases. The endpoints were risk of malignancy at pathology and rate of misdiagnosis for the surgical series, expressed as an odds ratio (OR) with 95 per cent confidence interval, and disease-specific survival (DSS) for the surveillance cohort investigated by the Kaplan-Meier method.

RESULTS

A total of 424 patients were identified. In the surgical series (229 patients), the rate of misdiagnosis was 19.2 per cent. The rate of malignant MCNs was 10.9 per cent (25 patients). The overall rate of malignancy, including misdiagnoses, was 11.3 per cent (26 patients). Predictors of malignancy were mural nodules (OR 27.75, 95 per cent c.i. 4.44-173.61; P < 0.001), size at least 50 mm (OR 13.39, 2.01 to 89.47; P = 0.007), and carbohydrate antigen 19.9 level (OR 3.98, 1.19 to 13.30; P = 0.025). In the absence of mural nodules and enhancing walls, none of the resected presumed MCNs smaller than 50 mm were malignant. Only patients with high-risk stigmata undergoing surgery experienced a significantly reduced 5-year DSS compared with all other patients (88 versus 100 per cent; P = 0.031).

CONCLUSION

Presumed MCNs with mural nodules, enhancing walls or cysts of 50 mm or larger should be considered for upfront surgical resection owing to the high risk of malignancy. In the absence of these features, the incidence of malignancy is negligible, favouring surveillance in selected patients given the low risk of malignancy and the high rate of misdiagnosis.

LAY SUMMARY

Malignant degeneration of presumed pancreatic mucinous cystic neoplasms takes several years, if it occurs at all. Mural nodules, enhancing walls or cysts of 50 mm or larger call for surgical resection owing to an increased risk of malignancy; otherwise, surveillance seems a good option.

Updates in diagnosis and management of pancreatic cysts

Incidental pancreatic cysts are commonly encountered with some cysts having malignant potential. The most common pancreatic cystic neoplasms include serous cystadenoma, mucinous cystic neoplasm and intraductal papillary mucinous neoplasm. Risk stratifying pancreatic cysts is important in deciding whether patients may benefit from endoscopic ultrasound (EUS) or surgical resection. Surgery should be reserved for patients with malignant cysts or cysts at high risk for developing malignancy as suggested by various risk features including solid mass, nodule and dilated main pancreatic duct. EUS may supplement magnetic resonance imaging findings for cysts that remain indeterminate or have concerning features on imaging. Various cyst fluid markers including carcinoembryonic antigen, glucose, amylase, cytology, and DNA markers help distinguish mucinous from nonmucinous cysts. This review will guide the practicing gastroenterologist in how to evaluate incidental pancreatic cysts and when to consider referral for EUS or surgery. For presumed low risk cysts, surveillance strategies will be discussed. Managing pancreatic cysts requires an individualized approach that is directed by the various guidelines.

Pathologic T1 and T2 encapsulated invasive carcinomas arising from mucinous cystic neoplasms of the pancreas have favorable prognosis and might be treated conservatively

Carcinoma arising from a mucinous cystic neoplasm (MCN) of the pancreas is termed MCN with associated invasive carcinoma (MCN-AIC) in the fifth WHO classification of digestive tumors (2019). The prognosis of this malignancy varies depending on the relationship of the invasive carcinoma to the cyst capsule, but limited data are available. This study identified 165 surgically resected MCNs including 15 MCN-AICs from a single center between 2008 and 2018 and analyzed their clinicopathologic features. The results confirmed that non-invasive MCNs were completely cured by surgery. All MCN-AICs showing an encapsulated invasion pattern (defined as invasive carcinoma limited to the ovarian-type stroma, cystic septa, and capsule) had an excellent prognosis with a 5-year survival rate of 100%, even when the size of the invasive component was up to stage T2. By contrast, MCN-AICs with extracapsular involvement had unfavorable clinical outcomes. Our study demonstrates that the pattern of invasion of MCN-AIC can predict patient prognosis. Pathologic stage T1 and T2 encapsulated MCN-AICs may be completely cured with surgical resection alone or when combined with postoperative chemotherapy.

Mucinous Cystadenocarcinoma of the Pancreas with Cyst Infection in a Male Patient

Follow-up computed tomography revealed a 40-mm pancreatic tail cyst in a 59-year-old man with type 1 diabetes mellitus. An intraductal papillary mucinous neoplasm was suspected; mucinous cystic neoplasm (MCN) was not considered because the patient was a man. During follow-up, cyst infection occurred but was improved by conservative treatment. At the 24-month follow up examination, cyst nodules had developed, corresponding to an increase in the carbohydrate antigen 19-9 level. Mucinous cystadenocarcinoma (MCC) was diagnosed pathologically based on distal pancreatectomy. A diagnosis of male MCN/MCC is often delayed, which may lead to a poor prognosis. MCN infection is also rare and poorly recognized. We observed an atypical male case of MCN/MCC.

Natural History and Treatment Trends in Pancreatic Cancer Subtypes

BACKGROUND

While pancreatic ductal adenocarcinoma is the most common form of pancreatic cancer, many other histologic forms of pancreatic cancer are also recognized. These histologic variants portray unique characteristics in terms of patient demographics, tumor behavior, survival, and responsiveness to treatments.

MATERIALS AND METHODS

Patients who underwent surgical resection of the pancreas for non-metastatic, invasive pancreatic cancer between 2004 and 2014 were selected from the National Cancer Data Base and categorized by histologic variant according to WHO classification guidelines. Patient demographics, tumor variables, treatment characteristics, and survival were compared between histologic groups and subgroups.

RESULTS

A total of 57,804 patients met inclusion and exclusion criteria and were grouped into eight major histologic categories. Survival analysis by the histologic group showed median overall survival of 20.2 months for ductal adenocarcinoma, 20.5 months for squamous cell carcinoma, 26.8 months for mixed acinar-neuroendocrine carcinomas, 52.6 months for cystic mucinous neoplasms with an associated invasive carcinoma, 67.5 months for acinar cell carcinoma, and 69.3 months for mesenchymal tumors. Median survival was not reached for neuroendocrine tumors and solid-pseudopapillary neoplasms, with 5-year overall survival rates of 84% and 97% respectively.

CONCLUSIONS

Rare subtypes of pancreatic cancer present unique clinicopathologic characteristics and display distinct tumor biologies. This study presents data on demographic, prognostic, treatment, and survival outcomes between rare forms of pancreatic neoplasms in order to aid understanding of the natural history and behavior of these neoplasms, with the hope of serving as a reference in clinical decision-making and ability to provide accurate prognostic information to patients.

Risk of malignancy in resected pancreatic mucinous cystic neoplasms

BACKGROUND

Pancreatic mucinous cystic neoplasms (MCNs) are rare mucin-producing cystic tumours defined by the presence of ovarian-type stroma. MCNs have a malignant potential and thus surgery is frequently performed. The aim of this cohort study was to define better the criteria for surgical resection in patients with MCN.

METHODS

This multicentre retrospective study included all resected MCNs between 2003 and 2015 in participating centres. Lesions without ovarian-type stroma were excluded. Patient characteristics, preoperative findings, histopathology findings and follow-up data were recorded.

RESULTS

The study included 211 patients; their median age was 53 (range 18-82) years, and 202 (95·7 per cent) were women. Median preoperative tumour size was 55 (range 12-230) mm. Thirty-four of the 211 (16·1 per cent) were malignant, and high-grade dysplasia (HGD) was found in a further 13 (6·2 per cent). One-third of MCNs in men were associated with invasive cancer, compared with 15·3 per cent in women. Five cases of malignant transformation occurred in MCNs smaller than 4 cm. All cases of malignancy or HGD were associated with symptoms or features of concern on preoperative cross-sectional imaging. In multivariable analysis, raised carbohydrate antigen 19-9 (odds ratio (OR) 10·54, 95 per cent c.i. 2·85 to 218·23; P < 0·001), tumour size (OR 4·23, 3·02 to 11·03; P = 0·001), mural nodules (OR 3·55, 1·31 to 20·55; P = 0·002) and weight loss (OR 3·40, 2·34 to 12·34; P = 0·034) were independent factors predictive of malignant transformation.

CONCLUSIONS

Small indeterminate MCNs with no symptoms or features of concern may safely be observed as they have a low risk of malignant transformation.

Mucinous cystadenoma of the pancreas associated with pregnancy. Case report and review of the literature

Objective. We present a rare pathology with uncommon onset. Background. Mucinous cystic pancreatic neoplasms (MCNs) are rare tumors, which generally occur in the fifth and sixth decades of women. Although some tumours are frankly malignant, all are in fact considered to be potentially malignant. Case report. We present the case of a 30-year-old patient, with a 16/11 cm tumor located in the pancreas body, which was diagnosed 8 months after birth. The preoperative assessment of the pancreatic lesion suggested the diagnosis of mucosal cyst neoplasm, without being able to determine its benign or malignant nature. Central pancreatectomy was performed with a good postoperative evolution. Histopathologic result was represented by mucinous pancreatic chistadenoma. Two years after surgical intervention, the patient presented no signs of recurrence or pancreatic (exocrine or endocrine) secretion deficiency. Conclusions. Preoperative imaging evaluation could be suggestive for mucinous cystic tumour, but this cannot specify however the nature of the tumor. The postpartum occurrence could establish a possible relationship between hormonal levels encountered during pregnancy and the development of this tumor, taking into considerations the ovarian-type stroma and the presence of hormone (estrogen and progesterone) receptors in this neoplasm. Central pancreatectomy without anastomosis preserves the functions of pancreas, and also decreases morbidity.

Molecular Diagnostics in the Evaluation of Pancreatic Cysts

Within the past few decades, there has been a dramatic increase in the detection of incidental pancreatic cysts. It is reported a pancreatic cyst is identified in up to 2.6% of abdominal scans. Many of these cysts, including serous cystadenomas and pseudocysts, are benign and can be monitored clinically. In contrast, mucinous cysts, which include intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, have the potential to progress to pancreatic adenocarcinoma. In this review, we discuss the current management guidelines for pancreatic cysts, their underlying genetics, and the integration of molecular testing in cyst classification and prognostication.

Anaplastic Pancreatic Carcinoma Arising Within a Mucinous Cystic Neoplasm of the Pancreas: A Case Report and a Brief Review of the Literature

Background: Anaplastic pancreatic carcinomas (APCs) are among the least frequently encountered pancreatic malignancies, ranging from 0.5% to 7% of all nonendocrine pancreatic malignancies. Furthermore, few cases of APCs have been described arising within a pancreatic mucinous cystic neoplasm (MCN). Case Presentation: A 36-year-old female presented with left upper quadrant pain and a 10 × 8 cm complex cystic mass in the pancreatic tail. Fine needle aspiration of the cyst showed papillary clusters of cells with mild cytological atypia, cyst fluid carcinoembryonic antigen >4000 ng/mL, and amylase of 25 U/L. After an open distal pancreatectomy and splenectomy, the specimen revealed an MCN with multifocal microscopic foci of invasive well-differentiated adenocarcinoma. After additional sampling, foci of undifferentiated malignancy-morphologically resembling sarcomas but with immunohistochemical staining consistent with anaplastic carcinoma-were identified. The patient had an uneventful recovery and is currently undergoing a regimen of gemcitabine-based adjuvant chemotherapy; she remains disease-free at 5 months after initial diagnosis. Conclusions: In this study, we describe a rare case of APC originating from a large pancreatic MCN lesion. This case underlines the importance of scrupulous pathological evaluation of the entire MCN epithelium and adds to the limited world literature of APC originating from pancreatic MCN lesions.

Association of Preoperative Risk Factors With Malignancy in Pancreatic Mucinous Cystic Neoplasms: A Multicenter Study

Importance

Pancreatic mucinous cystic neoplasms (MCNs) harbor malignant potential, and current guidelines recommend resection. However, data are limited on preoperative risk factors for malignancy (adenocarcinoma or high-grade dysplasia) occurring in the setting of an MCN.

Objectives

To examine the preoperative risk factors for malignancy in resected MCNs and to assess outcomes of MCN-associated adenocarcinoma.

Design, Setting, and Participants

Patients who underwent pancreatic resection of MCNs at the 8 academic centers of the Central Pancreas Consortium from January 1, 2000, through December 31, 2014, were retrospectively identified. Preoperative factors of patients with and without malignant tumors were compared. Survival analyses were conducted for patients with adenocarcinoma.

Main Outcomes and Measures

Binary logistic regression models were used to determine the association of preoperative factors with the presence of MCN-associated malignancy.

Results

A total of 1667 patients underwent resection of pancreatic cystic lesions, and 349 (20.9%) had an MCN (310 women [88.8%]; mean (SD) age, 53.3 [14.7] years). Male sex (odds ratio [OR], 3.72; 95% CI, 1.21-11.44; P = .02), pancreatic head and neck location (OR, 3.93; 95% CI, 1.43-10.81; P = .01), increased radiographic size of the MCN (OR, 1.17; 95% CI, 1.08-1.27; P < .001), presence of a solid component or mural nodule (OR, 4.54; 95% CI, 1.95-10.57; P < .001), and duct dilation (OR, 4.17; 95% CI, 1.63-10.64; P = .003) were independently associated with malignancy. Malignancy was not associated with presence of radiographic septations or preoperative cyst fluid analysis (carcinoembryonic antigen, amylase, or mucin presence). The median serum CA19-9 level for patients with malignant neoplasms was 210 vs 15 U/mL for those without (P = .001). In the 44 patients with adenocarcinoma, 41 (93.2%) had lymph nodes harvested, with nodal metastases in only 14 (34.1%). Median follow-up for patients with adenocarcinoma was 27 months. Adenocarcinoma recurred in 11 patients (25%), with a 64% recurrence-free survival and 59% overall survival at 3 years.

Conclusions and Relevance

Adenocarcinoma or high-grade dysplasia is present in 14.9% of resected pancreatic MCNs for which risks include male sex, pancreatic head and neck location, larger MCN, solid component or mural nodule, and duct dilation. Mucinous cystic neoplasm-associated adenocarcinoma appears to have decreased nodal involvement at the time of resection and increased survival compared with typical pancreatic ductal adenocarcinoma. Indications for resection of MCNs should be revisited.

Genomic Characterization of Low- and High-Grade Pancreatic Mucinous Cystic Neoplasms Reveals Recurrent KRAS Alterations in "High-Risk" Lesions

OBJECTIVES

Pancreatic ductal adenocarcinoma arises from the following 3 distinct precursor lesions: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm (MCN). Genetic abnormalities in the first 2 precursor lesions have been well characterized, but there are limited data on progression pathways in MCNs. This study aimed to characterize genomic differences between MCNs with low-grade (LG) and high-grade (HG) dysplasia or carcinoma.

METHODS

Neoplastic epithelium from surgical resections of 25 MCNs, 16 with LG dysplasia and 9 with HG dysplasia or invasive carcinoma, was analyzed by targeted massively parallel sequencing.

RESULTS

KRAS mutations were most frequent, present in 9 HG (100%) and 3 LG (19%) tumors, 2 of the latter also having discrete areas of HG tumor with the same mutation. TP53 mutations and CDKN2A loss were identified in 5 HG tumors (56%) each but not in LG tumors.

CONCLUSIONS

The low frequency of KRAS alterations in cysts without a HG component suggests that a subset of MCNs may have a low risk for malignant progression. Novel single-nucleotide variants that occur at a lower rate may help identify this group and provide a substrate for new diagnostic, prognostic, and therapeutic targets.

Pancreatic mucinous cystadenocarcinoma: Epidemiology and outcomes

BACKGROUND

Pancreatic mucinous cystadenocarcinoma is a rare malignancy. Our aim was to investigate the demographic, pathological characteristics, treatment modalities and survival of patients with mucinous cystadenocarcinoma via the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database analysis.

MATERIALS AND METHODS

This was a retrospective study of SEER database's records on patients with mucinous cystadenocarcinoma diagnosed from 1988 to 2012. Primary outcome measures were clinico-pathological characteristics, observed and disease-specific survival.

RESULTS

A total of 507 patients were identified. Median age at diagnosis was 67 years and most patients were female (68.4%). The tumors were mainly low grade (82.9%, grade I-II) and frequently localized (42.8%) in the body/tail of the pancreas (45.6%). According to Kaplan-Meier curves observed survival was 111 months (95%CI: 82.5, 139.5) vs 14 months (95% CI: 10.9, 17.1) vs 4 months (95%CI: 2.9, 5.1) for patients with localized, regional and distant disease, respectively. One-year disease-specific survival for patients with localized disease was 90.1%, vs. 56.7% for those with regional and 18.7% with distant tumor spread.

CONCLUSIONS

Mucinous cystadenocarcinomas tend to be low grade tumors, localized to the pancreatic body/tail. Surgery as the primary therapeutic intervention and tumor stage are independent predictors of disease-specific survival.

Clinical approach to incidental pancreatic cysts

The approach to incidentally noted pancreatic cysts is constantly evolving. While surgical resection is indicated for malignant or higher risk cysts, correctly identifying these highest risk pancreatic cystic lesions remains difficult. Using parameters including cyst size, presence of solid components, and pancreatic duct involvement, the 2012 International Association of Pancreatology (IAP) and the 2015 American Gastroenterological Association (AGA) guidelines have sought to identify the higher risk patients who would benefit from further evaluation using endoscopic ultrasound (EUS). Not only can EUS help further assess the presence of solid component and nodules, but also fine needle aspiration of cyst fluid aids in diagnosis by obtaining cellular, molecular, and genetic data. The impact of new endoscopic innovations with novel methods of direct visualization including confocal endomicroscopy require further validation. This review also highlights the differences between the 2012 IAP and 2015 AGA guidelines, which include the thresholds for sending patients for EUS and surgery and methods, interval, and duration of surveillance for unresected cysts.

Mucinous Cystic Neoplasms of the Pancreas: Are we Overestimating Malignant Potential?

Surgical resection is recommended for all mucinous cystic neoplasms (MCNs) of the pancreas as a result of: 1) lack of an accurate tumor marker for invasive cancer; 2) young age at diagnosis; and 3) historical studies revealing 36 per cent incidence of malignancy in resected lesions. This study compares the clinicopathologic and prognostic features of our series of resected MCNs to recent studies using the current International Association of Pancreatology (IAP) system. Thirty-eight resected MCNs were identified. Almost all patients were female (97.4%); median age at diagnosis was 53.5 years (interquartile range [IQR], 41.3 to 61.0). The majority occurred in the body/tail of the pancreas (86.8%); median size on computed tomography/magnetic resonance imaging was 5.0 cm (IQR, 3 to 8.8). Comparison of the five high-grade (HG, 13.2%) and 33 low-grade (86.8%) MCNs revealed that 1) patients were similar in age (55.0 vs 52.0 years, respectively) and 2) HG lesions were significantly larger on preoperative imaging (9.9 vs 3.5 cm) and final pathology (10.9 vs 3.5 cm). These data, taken together with five recent studies that adhere to the 2012 IAP criteria (385 total MCNs), reveal that a cutoff of less than 3 cm without mural nodules would have only missed one (0.26%) HG lesion. Surveillance of these lesions may be appropriate for some patients.

Diagnostic approach to pancreatic cysts

PURPOSE OF REVIEW

Diagnosis of pancreatic cysts remains challenging due to limitations of currently available radiologic and endoscopic tools. The diagnostic approach should focus on identifying mucinous and malignant cysts. Mucinous cysts require further differentiation to allow appropriate management.

RECENT FINDINGS

Although the overall rate of malignant pancreatic cysts is low, it remains higher than the general population. MRI with magnetic resonance cholangiopancreatography is the preferred imaging modality for pancreatic cysts. Attempts to improve diagnostic yield of endoscopic ultrasound-guided fine needle aspiration include performing cyst wall cytology and DNA analysis. The 2012 international consensus guidelines for mucinous cystic neoplasm and intraductal papillary mucinous neoplasm are superior to the original 2006 guidelines, although issues include the relatively poor ability to diagnose malignant cysts leading to unnecessary surgeries and the de-emphasis of cyst size. Cyst size remains an important predictor of malignancy. Translational research involving genomics, microRNA, proteomics, and metabolomics holds promise for improved biomarkers. Endoscopic innovations may safely aid in cyst diagnosis.

SUMMARY

Incremental improvements in pancreatic cyst diagnosis have occurred with new biomarkers and endoscopic tools requiring validation in large-scale studies.

Incidental Cystic Lesions in the Pancreas: Resect? EUS? Follow?

Pancreatic cysts challenge clinicians due to their increased incidental identification on radiology imaging, the limitations of currently available diagnostic tools, and potential for malignancy. Following initial identification of an incidental pancreatic cyst, a dedicated pancreatic protocol abdominal CT scan or MRI pancreas with MRCP should be performed. Surgical resection is recommended for all surgical candidates with MD-IPMN, mixed or combined type IPMN, mucinous cystic neoplasm, and solid pseudopapillary neoplasm. Serous cystadenoma may be followed with serial imaging unless the patient develops symptoms, the cyst is larger than 4 cm or rapidly growing, or diagnostic uncertainty remains despite thorough evaluation. Surveillance is also recommended for BD-IPMN without the following features concerning malignancy: obstructive jaundice with a cyst in the head of the pancreas; solid component; nodule; main pancreatic duct ≥10 mm; or cytology suspected or positive for malignancy. BD-IPMN ≥3 cm without concerning features may also be followed carefully, although surgical resection should be considered in surgically fit patients. EUS-FNA for cyst wall cytology, CEA, amylase, and occasionally k-ras mutation are also likely aids in the diagnosis of pancreatic cysts beyond radiologic imaging. This author typically recommends EUS-FNA to further evaluate cysts larger than 1 cm without definitive indication for resection. EUS is also appropriate in patients with solid component, nodule, or size ≥3 cm to aid in decision making, especially in older patients who may be less suitable surgical candidates. A multidisciplinary approach with a team of dedicated gastrointestinal radiologists, pancreatic surgeons, gastrointestinal pathologists, and gastroenterologists is essential for managing patients with pancreatic cysts.