Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines.

BACKGROUND: British Sarcoma Group guidelines for the management of GIST were initially informed by those published by the European Society of Clinical Oncology. This update was written by a group of experts to includes a discussion of the highlight improvements in our knowledge of the disease and recent treatment developments. The guidelines include sections on Incidence, Aetiology, Diagnosis, including risk assessment, Treatment and Follow-up. METHODS: A careful review of the literature was performed to ensure that wherever possible recommendations are supported by the results of clinical trials or substantive retrospective reports. Areas of uncertainty are indicated appropriately. CONCLUSION: Guidelines represent a consensus view of current best clinical practice. Where appropriate, key recommendations are given and the levels of evidence and strength of recommendation gradings are those used by the European Society for Medical Oncology (ESMO).

Anti-oxidant and anti-inflammatory potential of different polymer-based mesalamine delayed-release granules in TNBS-induced ulcerative colitis in wistar rats.

Ulcerative colitis (UC) is an inflammatory condition of colon characterized by severe damage to the innermost colon tissues. A number of studies described the use of medication delivery systems based on natural polymers like polysaccharides for the purpose of reaching the colon. In this research, polymer-based mesalamine delayed-release granules (DRGs) were tested for their antioxidant and anti-inflammatory efficacy against UC. Chitosan (C), pectin (P), and pectin-chitosan (PC) mesalamine (M) DRGs were prepared and characterized. Data revealed satisfactory compatibility, flow, packing properties, drug release pattern, and delayed drug release by DRGs. Wistar rats were treated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) (100 mg/kg) via rectal administration. Mesalamine and mesalamine DRGs (50 mg/kg) were administered orally separately for 14 days. Biomarkers of oxidative stress, inflammation, hematological tests, colon profile, and histopathology were performed. The findings demonstrated the good efficacy of the polysaccharides in delivering mesalamine to colon. Mesalamine and mesalamine DRGs based on various polymers showed significant antioxidant and anti-inflammatory effects in rats with UC. Mesalamine granules significantly attenuated colon lipid peroxidation, nitrites, myeloperoxidase activity, and interleukin-1ß levels, and improved anti-oxidants (GSH, SOD). Data showed upregulation of Nrf2 activity by mesalamine granules with CM-DRGs showing maximum effect. Mesalamine and different polymer-based mesalamine DRGs significantly attenuated TNBS-induced decline in body weight, ulcer severity, and colon damage. CM-DRGs showed the most pronounced ameliorative effect on colon and hematology parameters via anti-oxidant and anti-inflammatory activities. Chitosan can be used as a carrier for oral colon delivery of mesalamine in DRG formulation for enhanced therapeutic efficacy in UC.

A literature review and database of how the primary KIT/PDGFRA variant of a gastrointestinal stromal tumour predicts for sensitivity to imatinib.

It is well recognized that the primary KIT or PDGFRA variant of a gastrointestinal stromal tumour (GIST) can predict sensitivity to imatinib. However, these data are currently spread across a wide range of publications and have not been collated as one reference. A broad-ranging literature search was therefore performed to assemble such a database which should help optimize imatinib-based management of GIST patients henceforth. Having excluded wild type GISTs and results for imatinib used as adjuvant therapy, 79 publications (dated August 2001 to March 2022) underwent data extraction. These data on imatinib sensitivity were either derived from in vitro studies, predicted by in silico analysis or based on in vivo clinical patient response. Data interpretation carried some caveats: there was a potential for replication of patient-derived data between older and new publications; only predicted protein sequences were presented; the criteria used to record clinical response were not uniform across all publications; and imatinib dosage could vary between different clinical publications. However, these data showed broad agreement of imatinib sensitivity amongst similar subtypes of KIT or PDGFRA variant. There was also agreement between in vivo versus in vitro/in silico derived sensitivity data for most variants when both data types were available.

Demographic trends in the incidence of malignant appendiceal tumours in England between 1995 and 2016: Population-based analysis.

AIMS: Recent data suggest that the incidence of malignant appendiceal tumours is increasing. This study aimed to determine temporal trends in the incidence of malignant appendiceal tumours within England and a possible influence by demographic factors. METHODS: All incident cases of appendiceal tumours in patients aged 20 years and above were identified from the National Cancer Registration and Analysis Service database between 1995 and 2016 using ICD-9/10 codes. Cancers were categorized according to histology. Joinpoint regression analysis was used to investigate changes in age-standardized incidence rates by age, sex, histological subtype and index of multiple deprivation quintiles, based on socioeconomic domains (income, employment, education, health, crime, barriers to housing and services and living environment). Average annual per cent changes (AAPCs) were estimated by performing Monte-Carlo permutation analysis. RESULTS: A total of 7333 tumours were diagnosed and 7056 patients were analysed, comprising 3850 (54.6 per cent) neuroendocrine tumours (NETs), 1892 (26.8 per cent) mucinous adenocarcinomas and 1314 (18.6 per cent) adenocarcinoma (not otherwise specified). The overall incidence of appendiceal tumours increased from 0.3 per 100 000 to 1.6 per 100 000 over the study interval. Incidence rate increases of comparable magnitude were observed across all age groups, but the AAPC was highest among patients aged 20-29 years (15.6 per cent, 95 per cent c.i 12.7-18.6 per cent) and 30-39 years (14.2 per cent, 12.2-16.2 per cent) and lowest among those aged 70-79 years (6.8 per cent, 5.7-8.0 per cent). Similar incidence rate increases were reported across all socioeconomic deprivation quintiles and in both sexes. Analysis by grade of NET showed that grade 1 tumours accounted for 63 per cent between 2010 and 2013, compared with 2 per cent between 2000 and 2003. CONCLUSIONS: The incidence rate of malignant appendiceal tumours has increased significantly since 1995 and is mainly attributed to an increase in NETs. The increased diagnosis of low-grade NETs may in part be due to changes in pathological classification systems.

Clinical utility of GI pathology data: implications for practising pathologists.

Gastrointestinal (GI) tract pathology represents one of the largest individual specialties within cellular pathology departments globally. As with other specialties, clear communication with clinicians providing primary care for the patient is of utmost importance for optimal management and for appropriate use of resources such as endoscopy. A wide breadth of neoplastic and inflammatory conditions afflicts the GI tract. Here, we aim to illustrate how pathology reporting of GI tract specimens influences patient management and specifically how precise reporting of key parameters in different specimen types and different disease processes can directly impact patient care. We describe the potential clinical relevance of selected pathology data items pertinent to specific conditions and highlight areas of contention with respect to the significance of some pathology features. Recent guidelines are described where a change, for example, in diagnostic criteria for a condition is described, or criteria influencing further management such as endoscopic surveillance. The aim of this review is to focus on the clinical importance of careful written communication between the pathologist and primary clinician, illustrated by selective clinical scenarios involving the upper and lower GI tracts.

Simple biliary cysts of the liver can be lined by mucinous epithelium.

AIMS & METHODS: Simple biliary cysts of the liver are described to be lined by biliary epithelium and may be managed nonsurgically or by deroofing only. By contrast, its important differential diagnosis-mucinous cystic neoplasm (MCN)-is at least focally lined by mucinous epithelium, has malignant potential, and therefore should be resected. Following anecdotal observations in routine diagnostic practice, the following case series was assembled to confirm whether simple biliary cysts of the liver can be lined by mucinous epithelium. Detailed clinicoradiological review, including postoperative follow-up, was also completed to assess whether the presence of mucinous epithelium had any associations, including a risk of hepatobiliary neoplasia. RESULTS: Histological review of 21 simple biliary cysts received as surgical specimens over a 3- year period confirmed an absence of ovarian-like stroma in all cases. The lining epithelium of seven cysts showed focal supranuclear/apical mucin, as confirmed histochemically. Cysts with mucinous epithelium were generally larger and more often showed histological evidence of previous haemorrhage than cysts without this epithelium. There were no other statistically-significant differences in clinicoradiological features between cysts with and without mucinous epithelium, including at postoperative radiological follow-up. CONCLUSIONS: Focal mucinous epithelium can be present in at least one-third of surgically-managed, simple biliary cysts of the liver. Such epithelium may be metaplastic and should not be misinterpreted to indicate a diagnosis of MCN but, apart from this, appears to have no clinical significance. Ovarian-like stroma may therefore be the only histological feature that reliably distinguishes MCN from simple biliary cyst.

Determining airflow obstruction from tracheal sound analysis: simulated tests and evaluations in patients with acromegaly.

To evaluate the ability of tracheal sound analysis (TSA) to detect airflow obstruction, particularly in patients with acromegaly. A simulated analysis compared free airflow conditions with airflow through orifice plates 6, 8, 10 and 12 mm in diameter. Based on these results, TSA and spirometry examinations were performed on controls (n = 17) and patients with acromegaly (n = 17). The simulated study showed that airway obstruction and airflow values increased the values of power and a progressive displacement of the spectral distribution towards higher frequencies. In agreement with the simulation, airway obstruction in patients with acromegaly also resulted in increased values of power (p < 0.002) and displacement of the spectral distribution (p < 0.01). Significant associations were observed between the TSA parameters and the spirometry indices of obstruction (p < 0.02). In addition, the TSA parameters achieved adequate diagnostic accuracy (AUC ≥ 0.887). The present study provides evidence that TSA during resting breathing would provide adequate biomarkers of early upper airway changes in patients with acromegaly. TSA is carried out during spontaneous ventilation, requires little from the patient, and is fast and inexpensive. Taken together, these practical considerations and the results of the present study suggest that TSA may improve lung function tests for patients with acromegaly. Summary of the study, overall design flow and the main results obtained.

Forest maturity has a stronger influence on the prevalence of spider monkeys than howler monkeys in an anthropogenically impacted rainforest landscape.

The transformation and depletion of primary forest over the past few decades have placed almost half of the world's primate species under the threat of extinction. Developing any successful conservation program for primates requires distribution and demography data, as well as an understanding of the relationships between these factors and their habitat. Between March and June 2010 and 2011 we collected data on the presence and demographic parameters of howler and spider monkeys by carrying out surveys, and validated our findings using local knowledge. We then examined the relationship between forest type and the presence of these primates at 54 sites in the northern area of the Selva Zoque Corridor, Mexico. We detected 86 spider monkey groups across 31 plots and censused 391 individuals (mean ± SD = 5.9 ± 3.0 individuals per sub-group, n = 67 sub-groups). We also detected 69 howler monkey groups across 30 plots and censused 117 individuals (mean ± SD = 5.3 ± 2.4 individuals per group, n = 22 groups). Howler monkey presence was not related to any specific vegetation type, while spider monkeys were present in areas with a higher percentage of tall forest (trees > 25 m high). Overall, spider monkeys were more prevalent than howler monkeys in our sampling sites and showed demographic characteristics similar to those in better protected areas, suggesting that the landscape features in the Uxpanapa Valley are suitable for their needs. Conversely, howler monkey presence was found to be more limited than in other regions, possibly due to the extended presence of spider monkeys.

Sampling endoscopically normal large bowel mucosa from patients presenting with elevated faecal calprotectin levels is not clinically justified.

AIMS AND METHODS: Faecal calprotectin (FCP) measurement is used especially to investigate for inflammatory bowel disease (IBD). To assess the utility of sampling endoscopically normal large bowel among patients first presenting with elevated FCP, this study identified 115 such patients out of 652 patients with elevated FCP from approximately 6000 primary care tests processed over 15 months. RESULTS: 23 cohort patients showed histologically abnormal large bowel biopsies. Only four cases demonstrated acute inflammation and two such patients only showed scattered cryptitis and did not develop IBD. A third patient demonstrated similar histology but, following repeat colonoscopy, her elevated FCP was attributed to small intestinal inflammation. Only the fourth patient's large bowel biopsies showed features suggesting Crohn's disease, but this represented an IBD detection rate out of 115 sets of large bowel biopsies of 0.9%. CONCLUSIONS: Sampling of endoscopically normal large bowel among patients first presenting with elevated FCP is not clinically justified.

Particle release from refit operations in shipyards: Exposure, toxicity and environmental implications.

European harbours are known to contribute to air quality degradation. While most of the literature focuses on emissions from stacks or logistics operations, ship refit and repair activities are also relevant aerosol sources in EU harbour areas. Main activities include abrasive removal of filler and spray painting with antifouling coatings/primers/topcoats. This work aimed to assess ultrafine particle (UFP) emissions from ship maintenance activities and their links with exposure, toxicity and health risks for humans and the aquatic environment. Aerosol emissions were monitored during mechanical abrasion of surface coatings under real-world operating conditions in two scenarios in the Mallorca harbour (Spain). Different types of UFPs were observed: (1) highly regular (triangular, hexagonal) engineered nanoparticles (Ti-, Zr-, Fe-based), embedded as nano-additives in the coatings, and (2) irregular, incidental particles emitted directly or formed during abrasion. Particle number concentrations monitored were in the range of industrial activities such as drilling or welding (up to 5 ∗ 105/cm3, mean diameters <30 nm). The chemical composition of PM4 aerosols was dominated by metallic tracers in the coatings (Ti, Al, Ba, Zn). In vitro toxicity of PM2 aerosols evidenced reduced cell viability and a moderate potential for cytotoxic effects. While best practices (exhaust ventilation, personal protective equipment, dust removal) were in place, it is unlikely that exposures and environmental release can be fully avoided at all times. Thus, it is advisable that health and safety protocols should be comprehensive to minimise exposures in all types of locations (near- and far-field) and periods (activity and non-activity). Potential release to coastal surface waters of metallic engineered and incidental nanomaterials, as well as fine and coarse particles (in the case of settled dust), should be assessed and avoided.

The Bowel Cancer Screening Programme Expert Board: an analysis of activity during 2017-2020.

AIMS: The inception of the National Health Service Bowel Cancer Screening Programme in England in 2006 highlighted the fact that the differential diagnosis between the presence of epithelial misplacement and adenocarcinoma occurring in colorectal adenomas is problematic. The pathology Expert Board (EB) was created to facilitate the review of difficult cases by a panel of three experienced gastrointestinal pathologists. This article describes a review of the work of the EB over a 4-year period (2017-2020). METHODS AND RESULTS: Four hundred and thirty polyps were referred to the EB from 193 pathologists and 76 hospitals during this time. The EB diagnosis was benign for 67%, malignant for 28%, and equivocal for 2% (with no consensus in the remainder). The most common diagnosis change made by the EB was from malignant to benign-made in 50% of polyps referred with an initially malignant diagnosis. The level of agreement between the individual EB members was 'good' (kappa score of 0.619) but that between the EB and the referring diagnosis was 'poor' (kappa score of 0.149). Data from one EB member indicated that the presence of lamina propria, features of torsion and cytological similarity between the superficial and deep glands were predictors of a benign diagnosis, whereas the presence of irregular neoplastic glands, a desmoplastic reaction and lymphovascular invasion were commonly observed features in polyps with a malignant diagnosis. CONCLUSION: Diagnostic agreement between EB members is better than that between the EB and referring pathologists. There was a consistent trend for the EB to change diagnoses from malignant to benign.

UK food and nutrition security during and after the COVID-19 pandemic.

The COVID-19 pandemic is a major shock to society in terms of health and economy that is affecting both UK and global food and nutrition security. It is adding to the 'perfect storm' of threats to society from climate change, biodiversity loss and ecosystem degradation, at a time of considerable change, rising nationalism and breakdown in international collaboration. In the UK, the situation is further complicated due to Brexit. The UK COVID-19 F ood and N utrition S ecurity project, lasting one year, is funded by the Economic and Social Research Council and is assessing the ongoing impact of COVID-19 on the four pillars of food and nutrition security: access, availability, utilisation and stability. It examines the food system, how it is responding, and potential knock on effects on the UK's food and nutrition security, both in terms of the cascading risks from the pandemic and other threats. The study provides an opportunity to place the initial lessons being learnt from the on-going responses to the pandemic in respect of food and nutrition security in the context of other long-term challenges such as climate change and biodiversity loss.

Calponin and MUC6 complement inhibin as diagnostic immunomarkers of serous cystadenoma in endoscopic ultrasound-guided aspiration/biopsy specimens.

AIMS: Because serous cystadenoma (SCA) does not usually require excision, it is critical to distinguish it from differential diagnoses which do, especially neuroendocrine tumour (NET). The gold standard for diagnosing SCA is assessment of endoscopic ultrasound-guided fine needle aspiration/biopsy (EUS-FNAB) material. Inhibin immunohistochemistry aids this assessment, but such positivity is not absolutely sensitive or specific to SCA. The following is the largest known study of SCA EUS-FNAB specimens and the first to compare four potential SCA immunomarkers between themselves and inhibin, compared against NET. METHODS AND RESULTS: Immunohistochemistry for calponin, mucin 6 (MUC6), glucose transporter 1 (GLUT1) and vascular endothelial growth factor A (VEGFA) was performed on 30 EUS-FNAB and three resection specimens of SCA and 32 EUS-FNAB specimens of NET. GLUT1 and VEGFA were suboptimal as diagnostic immunomarkers of SCA, being expressed by 10 and 44% of NETs, respectively. Further, their expression by cellular constituents of blood which often contaminate EUS-FNAB specimens hampered identification of neoplastic cells, especially in hypocellular samples. While 19% of NETs showed nuclear MUC6 positivity, cytoplasmic expression of the protein showed 100% specificity and sensitivity as an SCA marker. However, assessing MUC6 in EUS-FNAB specimens must also consider the protein's focal expression in physiological pancreatic, gastric or duodenal tissues, which can contaminate these specimens. Calponin was less sensitive (71% versus 100%) but more specific (100% versus 91%) than inhibin, although easier to assess in EUS-FNAB specimens than MUC6. CONCLUSIONS: Of the four potential immunomarkers of SCA suggested by the existing literature, calponin and MUC6 are useful complementary studies to inhibin for application to EUS-FNAB specimens.

miR-210 and miR-152 as Biomarkers by Liquid Biopsy in Invasive Ductal Carcinoma.

Detecting circulating microRNAs (miRNAs; miRs) by means of liquid biopsy is an important tool for the early diagnosis and prognosis of breast cancer (BC). We aimed to identify and validate miR-210 and miR-152 as non-invasive circulating biomarkers, for the diagnosis and staging of BC patients, confirming their involvement in tumor angiogenesis. METHODS: RT-qPCR was performed and MiRNA expression analysis was obtained from plasma and fragments of BC and benign breast condition (BBC) women patients, plus healthy subjects. Additionally, the immunohistochemistry technique was carried out to analyze the expression of target proteins. RESULTS: Tumor fragments showed increased expression of oncomiR-210 and decreased expression of miR-152 tumoral suppressor. Both miRNAs were increased in plasma samples from BC patients. The receiver operating characteristic (ROC) curve analysis revealed that only the expression of oncomiR-210 in tissue samples and only the expression of the miR-152 suppressor in plasma have the appropriate sensitivity and specificity for use as differential biomarkers between early/intermediate and advanced stages of BC patients. In addition, there was an increase in the expression of hypoxia-inducible factor 1-alpha (HIF-1α), insulin-like growth factor 1 receptor (IGF-1R), and vascular endothelial growth factor (VEGF) in BC patients. On the contrary, a decrease in Von Hippel-Lindau (VHL) protein expression was observed. CONCLUSIONS: This study showed that increased levels of miR-210 and decreased levels of miR152, in addition to the expressions of their target proteins, could indicate, respectively, the oncogenic and tumor suppressive role of these miRNAs in fragments. Both miRNAs are potential diagnostic biomarkers for BC by liquid biopsy. In addition, miR-152 proved to be a promising biomarker for disease staging.

The diagnostic and clinical significance of granulomas in gastrointestinal biopsies from haematopoietic transplant patients.

AIMS: The diagnostic and clinical significance of granulomas in gastrointestinal (GI) biopsies from haematopoietic transplant patients remains disputed, especially following the proposal of cord colitis syndrome (CCS) as a new entity. The aim of the following study was to explore this controversy by identifying such biopsies with granulomas and detailing their clinicopathological associations. METHODS AND RESULTS: Twelve patients with granuloma-containing biopsies were identified from across three scenarios: prospectively during a GI pathologist's routine practice over a period of 5 years; retrospectively from a cohort of transplant patients with clinically validated GI graft versus host disease (GVHD); and retrospectively from a cohort of patients who had received umbilical cord blood (UCB). Their clinicopathological assessments (which included unique long-term patient follow-up) showed that granulomas are only rarely seen across all GI biopsies from haematopoietic transplant patients, and may uncommonly constitute a histological feature of GI GVHD. Granulomas-and especially well-defined, non-cryptolytic ones-are more commonly present in GI biopsies from UCB recipients, but do not show any accompanying histological features that are different from those seen in granuloma-containing biopsies from other patient groups. Furthermore, the three UCB recipients with granuloma-containing biopsies were clinically diagnosed with GVHD rather than CCS. Finally, polymorphic post-transplant lymphoproliferative disorder (PTLD) can present histologically as GI granulomatous inflammation that mimics Crohn's disease. CONCLUSIONS: Granulomas in GI biopsies of haematopoietic transplant patients may often indicate a treatable aetiology such as GVHD or PTLD. Granulomas are more commonly seen in GI biopsies from UCB recipients, but do not necessarily indicate a diagnosis of CCS.

Current dilemmas in the pathological staging of colorectal cancer: the results of a national survey.

AIMS: Accurate and consistent pathological staging of colorectal carcinoma (CRC) in resection specimens is especially crucial to guide adjuvant therapy. The aim of this study was to assess whether certain staging scenarios yield discordant opinions in the setting of current international and UK national guidelines. METHODS AND RESULTS: Members of the UK Gastrointestinal Pathology External Quality Assurance Scheme were invited to complete an anonymous, on-line survey that presented 15 scenarios related to pT or pR staging of CRC, and three questions about the respondent. The survey invitation was e-mailed to 405 pathologists, and 184 (45%) responses were received. The respondents had discordant opinions on whether and how CRC pT or pR staging is affected by: acellular mucin lakes and duration after short-course radiotherapy; the nature of the carcinoma at a resection margin or peritoneal surface; and microscopic evidence of perforation. This discordance was rarely related to the respondent's occupation type, and was not related to duration of work as a consultant or the staging guidelines used. CONCLUSIONS: This survey confirms that there remain several clinically critical but unresolved pT and pR staging issues for CRC. These issues therefore deserve attention in future versions of international and national staging guidelines.

Next-generation sequencing demonstrates the rarity of short kinase variants specific to quadruple wild-type gastrointestinal stromal tumours.

AIM: There is no known specific biomarker or genetic signal for quadruple wild-type (qWT) gastrointestinal stromal tumours (GISTs). By next-generation sequencing (NGS) of different GIST subgroups, this study aimed to characterise such a biomarker especially as a potential therapeutic target. METHODS AND RESULTS: An NGS panel of 672 kinase genes was applied to DNA extracted from 11 wild-type GISTs (including three qWT GISTs) and 5 KIT/PDGFRA mutated GISTs. Short variants which were present in qWT GISTs but no other GIST subgroup were shortlisted. After removing common population variants, in silico-classified deleterious variants were found in CSNK2A1, MERTK, RHEB, ROCK1, PIKFYVE and TRRAP. None of these variants were demonstrated in a separate cohort of four qWT GISTs. CONCLUSIONS: Short kinase variants which are specific to qWT GISTs are rare and are not universally demonstrated by this whole subgroup. It is therefore possible that the current definition of qWT GIST still covers a heterogenous population.

My approach to endoscopic ultrasound-guided fine-needle aspiration biopsy specimens of the pancreas.

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is the optimal method for sampling lesions of the pancreas. This procedure is being performed at increasing numbers of hospitals and therefore, more and more cellular pathology departments are having to process and report EUS-FNAB specimens. This article outlines the advantages of using tissue/cell block preparation to process these specimens. In particular, such preparation concentrates, conserves and preserves sampled material which is then available for a full array of further analyses. Tissue/cell block preparation also enables EUS-FNAB specimens to be assessed by a wider range of cellular pathologists. This article demonstrates how a tissue/cell block protocol permits the diagnosis of the full range of pancreatic pathologies sampled by EUS-FNAB. The protocol is identical for all these pathologies (including both solid and cystic lesions) and is simple at all stages of the specimen pathway, from collection to processing to assessment.

Cell block processing is optimal for assessing endoscopic ultrasound fine needle aspiration specimens of pancreatic mucinous cysts.

AIMS: The cell block technique for assessing endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) specimens from pancreatic mucinous cystic lesions (MCLs) was systematically evaluated for the first time, including comparisons with three traditional methods of assessing such specimens. METHODS: The prospective arm comprised EUS-FNA specimens from EUS-suspected pancreatic MCLs. The retrospective arm comprised EUS-FNA specimens from pancreatic MCLs surgically resected before the study start. For each specimen, these data points were collected: macroscopic likelihood of mucin, cyst fluid carcinoembryonic antigen (CEA) level and presence of mucin in air-dried, direct smears and in cell block preparations. RESULTS: The prospective and retrospective arms of the study comprised 80 and 30 EUS-FNA specimens, respectively. Seven prospective cases led to surgical resections during the study, and therefore, 37 EUS-FNA specimens were confirmed to have originated from MCLs. In the prospective arm, macroscopic mucin was suspected, cyst fluid CEA level exceeded 192 ng/mL, mucin was detected in direct smears and cell block preparations in 78%, 30%, 39% and 73% of cases, respectively. Of the 37 specimens confirmed to originate from MCLs, macroscopic mucin assessment, cyst fluid CEA level, direct smear mucin assessment and cell block mucin assessment had sensitivities for diagnosing MCL of 87%, 45%, 45% and 81%, respectively. CONCLUSIONS: Cell block preparations are as likely to identify mucin from pancreatic MCLs as macroscopic assessment but are twice as likely to diagnose MCL than direct smears and fluid CEA biochemistry. The cell block technique is easy for sample collection and processing especially because these are identical for solid and cystic pancreatic lesions.