Long-term Outcomes of Ampullary Adenoma According to Resected Margin Status after Endoscopic Papillectomy.

Background/Aims: : Endoscopic papillectomy (EP) is increasingly used as an alternative to surgery for managing benign ampullary neoplasms. However, post-EP resection margins are often positive or indeterminate, and there is no consensus on the management of ampullary adenomas with positive or indeterminate margins after EP. This study was designed to compare the long-term outcomes between resected margin-negative (RMN) and resected margin-positive/indeterminate (RMPI) groups and to identify factors associated with clinical outcomes. Methods: : This retrospective analysis included patients with ampullary adenoma without evidence of adenocarcinoma who underwent EP between 2004 and 2016. The RMN and RMPI groups were compared for recurrence rates and recurrence-free duration during a mean follow-up duration of 71.7±39.8 months. Factors related to clinical outcomes were identified using multivariate analysis. Results: : Of the 129 patients who underwent EP, 82 were in the RMN group and 47 were in the RMPI group. The RMPI group exhibited a higher recurrence rate compared to the RMN group (14.6% vs 34.0%, p=0.019). However, the recurrence-free duration was not significantly different between the groups (34.7±32.6 months vs 36.2±27.4 months, p=0.900). Endoscopic treatment successfully managed recurrence in both groups (75% vs 75%). Submucosal injection was a significant risk factor for residual lesions (hazard ratio, 4.11; p=0.009) and recurrence (hazard ratio, 2.57; p=0.021). Conclusions: : Although ampullary adenomas with positive or indeterminate margins after EP showed a higher rate of recurrence at long-term follow-up, endoscopic treatment was effective with favorable long-term outcomes. Submucosal injection prior to resection was associated with increased risk of recurrence and residual lesions.

Prognostic performance of microscopic size measurements in small invasive carcinomas arising in intraductal papillary mucinous neoplasms of the pancreas.

AIMS: Small invasive carcinomas arising in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas can present as multiple, small foci. In such cases, there is no clear optimal measurement method for determining the invasive size for tumour staging and prognostication. METHODS: In all, 117 small invasive IPMNs (size of largest invasive component ≤2 cm) from seven institutions (2000-2016) were reviewed, and all individual foci of invasive carcinoma were measured. T stages (AJCC 8th edition) based on the largest single focus size (LS), average size of all foci (AS), and total sum of all foci (TS) were examined in association with clinicopathologic parameters and patient outcomes. RESULTS: The cohort comprised IPMNs with invasive tubular-type (n = 82, 70%) and colloid-type (n = 35, 30%) carcinomas. The mean LS, AS, and TS were 0.86, 0.71, and 1.32 cm, respectively. Based on the LS, AS, and TS, respectively, 48, 65, and 39 cases were classified as pT1a; 22, 18, and 11 cases as pT1b; and 47, 34, and 50 cases as pT1c. Higher pT stages based on all measurements were significantly associated with small vessel, large vessel, and perineural invasion (P < 0.05). LS-, AS-, and TS-based pT stages were not significantly associated with recurrence-free survival (RFS) or overall survival (OS) by univariate or multivariate analyses. However, among tubular-type carcinomas, higher LS-, AS-, and TS-based pT stages trended with lower RFS (based on 1-, 3-, and 5-year survival rates). All microscopic measurement methods were most predictive of RFS and OS using a 1.5-cm cutoff, with LS significantly associated with both RFS and OS by univariate and multivariate analysis. CONCLUSIONS: For invasive tubular-type carcinomas arising in IPMN, microscopic size-based AJCC pT stages were not significant predictors of patient outcomes. However, for LS, a size threshold of 1.5 cm was optimal for stratifying both RFS and OS. The AJCC 8th ed. may not be applicable for stratifying small invasive IPMNs with colloid-type histology that generally portend a more favourable prognosis.

Practice guidelines for managing extrahepatic biliary tract cancers.

Backgrounds/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions: The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Malignant potential of neuroendocrine microtumor of the pancreas harboring high-grade transformation: lesson learned from a patient with von Hippel-Lindau syndrome.

Pancreatic neuroendocrine microtumor (PNEMT) is a neuroendocrine tumor (NET) < 0.5 cm in diameter, and it is considered benign. We report a PNEMT with high-grade transformation (HGT). A man in his 60s with von Hippel-Lindau syndrome underwent surgical resection of a NET. A second sub-centimeter nodule with a nodule-in-nodule pattern was discovered. The 0.4 cm outer nodule contained clear columnar cells with round nuclei and indistinct nucleoli, while the 0.1 cm inner nodule had eosinophilic cells with an increased nuclear to cytoplasmic ratio, vesicular nuclei, and prominent nucleoli. Tumor cells in the outer and inner nodules were synaptophysin and chromogranin positive. Only the inner nodule was p53 positive, while the outer nodule was exclusively positive for carbonic anhydrase 9 and vimentin. The Ki-67 labeling indices for the outer and inner nodules were 2.1% (grade 1) and 44.3% (grade 3), respectively. This nodule was determined to be a PNEMT with HGT. Our findings suggest that a PNEMT may not always be benign and can undergo HGT.

Open-top Bessel beam two-photon light sheet microscopy for three-dimensional pathology.

Nondestructive pathology based on three-dimensional (3D) optical microscopy holds promise as a complement to traditional destructive hematoxylin and eosin (H&E) stained slide-based pathology by providing cellular information in high throughput manner. However, conventional techniques provided superficial information only due to shallow imaging depths. Herein, we developed open-top two-photon light sheet microscopy (OT-TP-LSM) for intraoperative 3D pathology. An extended depth of field two-photon excitation light sheet was generated by scanning a nondiffractive Bessel beam, and selective planar imaging was conducted with cameras at 400 frames/s max during the lateral translation of tissue specimens. Intrinsic second harmonic generation was collected for additional extracellular matrix (ECM) visualization. OT-TP-LSM was tested in various human cancer specimens including skin, pancreas, and prostate. High imaging depths were achieved owing to long excitation wavelengths and long wavelength fluorophores. 3D visualization of both cells and ECM enhanced the ability of cancer detection. Furthermore, an unsupervised deep learning network was employed for the style transfer of OT-TP-LSM images to virtual H&E images. The virtual H&E images exhibited comparable histological characteristics to real ones. OT-TP-LSM may have the potential for histopathological examination in surgical and biopsy applications by rapidly providing 3D information.

Clinical outcomes of second-line therapy following disease progression on first-line modified FOLFIRINOX for borderline resectable and locally advanced pancreatic adenocarcinoma.

BACKGROUND: Modified FOLFIRINOX (mFOLFIRINOX) is one of the standard first-line therapies in borderline resectable pancreatic cancer (BRPC) and locally advanced unresectable pancreatic cancer (LAPC). However, there is no globally accepted second-line therapy following progression on mFOLFIRINOX. METHODS: Patients with BRPC and LAPC (n = 647) treated with first-line mFOLFIRINOX between January 2017 and December 2020 were included in this retrospective analysis. The details of the treatment outcomes and patterns of subsequent therapy after mFOLFIRINOX were reviewed. RESULTS: With a median follow-up duration of 44.2 months (95% confidence interval [CI], 42.3-47.6), 322 patients exhibited disease progression on mFOLFIRINOX-locoregional progression only in 177 patients (55.0%) and distant metastasis in 145 patients (45.0%). The locoregional progression group demonstrated significantly longer post-progression survival (PPS) than that of the distant metastasis group (10.1 vs. 7.3 months, p = 0.002). In the locoregional progression group, survival outcomes did not differ between second-line chemoradiation/radiotherapy and systemic chemotherapy (progression-free survival with second-line therapy [PFS-2], 3.2 vs. 4.3 months; p = 0.649; PPS, 10.7 vs. 10.2 months; p = 0.791). In patients who received second-line systemic chemotherapy following progression on mFOLFIRINOX (n = 211), gemcitabine plus nab-paclitaxel was associated with better disease control rates (69.2% vs. 42.3%, p = 0.005) and PFS-2 (3.8 vs. 1.7 months, p = 0.035) than gemcitabine monotherapy. CONCLUSIONS: The current study showed the real-world practice pattern of subsequent therapy and clinical outcomes following progression on first-line mFOLFIRINOX in BRPC and LAPC. Further investigation is necessary to establish the optimal therapy after failure of mFOLFIRINOX.

Prognostic value of CT-based radiomics in grade 1-2 pancreatic neuroendocrine tumors.

BACKGROUND: Surgically resected grade 1-2 (G1-2) pancreatic neuroendocrine tumors (PanNETs) exhibit diverse clinical outcomes, highlighting the need for reliable prognostic biomarkers. Our study aimed to develop and validate CT-based radiomics model for predicting postsurgical outcome in patients with G1-2 PanNETs, and to compare its performance with the current clinical staging system. METHODS: This multicenter retrospective study included patients who underwent dynamic CT and subsequent curative resection for G1-2 PanNETs. A radiomics-based model (R-score) for predicting recurrence-free survival (RFS) was developed from a development set (441 patients from one institution) using least absolute shrinkage and selection operator-Cox regression analysis. A clinical model (C-model) consisting of age and tumor stage according to the 8th American Joint Committee on Cancer staging system was built, and an integrative model combining the C-model and the R-score (CR-model) was developed using multivariable Cox regression analysis. Using an external test set (159 patients from another institution), the models' performance for predicting RFS and overall survival (OS) was evaluated using Harrell's C-index. The incremental value of adding the R-score to the C-model was evaluated using net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS: The median follow-up periods were 68.3 and 59.7 months in the development and test sets, respectively. In the development set, 58 patients (13.2%) experienced recurrence and 35 (7.9%) died. In the test set, tumors recurred in 14 patients (8.8%) and 12 (7.5%) died. In the test set, the R-score had a C-index of 0.716 for RFS and 0.674 for OS. Compared with the C-model, the CR-model showed higher C-index (RFS, 0.734 vs. 0.662, p = 0.012; OS, 0.781 vs. 0.675, p = 0.043). CR-model also showed improved classification (NRI, 0.330, p < 0.001) and discrimination (IDI, 0.071, p < 0.001) for prediction of 3-year RFS. CONCLUSIONS: Our CR-model outperformed the current clinical staging system in prediction of the prognosis for G1-2 PanNETs and added incremental value for predicting postoperative recurrence. The CR-model enables precise identification of high-risk patients, guiding personalized treatment planning to improve outcomes in surgically resected grade 1-2 PanNETs.

Somatostatin receptor 2 (SSTR2) expression is associated with better clinical outcome and prognosis in rectal neuroendocrine tumors.

Somatostatin analogues have recently been used as therapeutic targets for metastatic or surgically unresectable gastroenteropancreatic (GEP) neuroendocrine tumors (NETs), and associated somatostatin receptor (SSTR) expression has been well demonstrated in most GEP NETs, with the exception of rectal NETs. SSTR2 immunohistochemical expressions were evaluated in 350 surgically or endoscopically resected rectal NETs and compared to clinicopathologic factors. SSTR2 expression was observed in 234 (66.9%) rectal NET cases and associated tumors with smaller size (p = 0.001), low pT classification (p = 0.030), low AJCC tumor stage (p = 0.012), and absence of chromogranin expression (p = 0.009). Patients with rectal NET and SSTR2 expression had significantly better overall survival than those without SSTR2 expression both by univariable (p = 0.006) and multivariable (p = 0.014) analyses. In summary, approximately two-thirds of rectal NETs expressed SSTR2. SSTR2 expression was significantly associated with favorable behavior and good overall survival in patients with rectal NETs. Furthermore, SSTR2 expression can be used as prognostic factors. When metastatic disease occurs, SSTR2 expression can be used a possible target for somatostatin analogues.

Uncovering the clinicopathological features of early recurrence after surgical resection of pancreatic cancer.

To identify risk factors and biomarker for early recurrence in patients diagnosed with pancreatic cancer who undergo curative resection. Early recurrence after curative resection of pancreatic cancer is an obstacle to long-term survival. We retrospectively reviewed 162 patients diagnosed with pancreatic cancer who underwent curative resection. Early recurrence was defined as recurrence within 12 months of surgery. We selected S100A2 as a biomarker and investigated its expression using immunohistochemistry. Of the total, 79.6% (n = 129) of patients received adjuvant chemotherapy after surgery and 117 (72.2%) experienced recurrence, of which 73 (45.1%) experience early recurrence. In multivariate analysis, age < 60 years, presence of lymph node metastasis, and no adjuvant chemotherapy were significantly associated with early recurrence (all P < 0.05). The proportion of patients with high S100A2 expression (H-score > 5) was significantly lower in the early recurrence group (41.5% vs. 63.3%, P = 0.020). The cumulative incidence rate of early recurrence was higher in patients with an S100A2 H-score < 5 (41.5% vs. 63.3%, P = 0.012). The median overall survival of patients with higher S100A2 expression was longer than those with lower S100A2 expression (median 30.1 months vs. 24.2 months, P = 0.003). High-risk factors for early recurrence after surgery for pancreatic cancer include young age, lymph node metastasis, and no adjuvant therapy. Neoadjuvant treatment or intensive adjuvant therapy after surgery may improve the prognosis of patients with high-risk signatures. In patients who receive adjuvant therapy, high S100A2 expression is a good predictor.

Enteroblastic cholangiocarcinoma: An uncommon, underrecognized subtype of bile duct cancer.

Enteroblastic carcinoma is clinically characterized by an elevated serum level of alpha-fetoprotein (AFP) and is histologically characterized by cancer cells with a clear cytoplasm and 'blastic' coarse chromatin. It sometimes has an element of hepatoid carcinoma; therefore, these two neoplasms are often regarded as sister entities. Although hepatoid carcinoma in the biliary tree has been reported, enteroblastic cholangiocarcinoma is extremely uncommon. In the present study, four cases of enteroblastic cholangiocarcinoma were examined. Tumors were located inside the liver (n = 2) or common bile duct (n = 2). The two intrahepatic cases had a history of primary sclerosing cholangitis, and serum AFP levels were elevated in both. One unresectable case was diagnosed by needle liver biopsy, while the remaining three underwent surgical resection. Histologically, all cases showed similar microscopic features. Cuboidal or polygonal cancer cells with the characteristic clear cytoplasm and subnuclear vacuoles were arranged in a papillary, micropapillary, tubular, or solid architecture. One case had an element of pancreatobiliary-type adenocarcinoma, while a hepatoid carcinoma element was not observed in any cases. All cases were positive for AFP, glypican 3, and SALL4, with SALL4 being the most widely expressed. Heppar-1 and arginase-1 were negative, except for one case, which was positive for Heppar-1. In conclusion, enteroblastic cholangiocarcinoma is an uncommon subtype of biliary tract malignancy. These cases may have been categorized as 'clear cell' cholangiocarcinoma. Although enteroblastic cholangiocarcinoma seems to occur more commonly in extrahepatic regions, including the gallbladder, it may also develop in the liver, particularly in patients with primary sclerosing cholangitis.

Endoscopic mucosal resection using anchored snare Tip-in versus precut technique for small rectal neuroendocrine tumors.

BACKGROUND/AIMS: Small rectal neuroendocrine tumors (NETs) can be treated with modified endoscopic mucosal resection (EMR). However, an optimal EMR method remains to be established. We aimed to assess the non-inferiority of Tip-in EMR versus precut EMR (EMR-P) for treating rectal NETs. METHODS: This prospective, multicenter, randomized controlled trial enrolled patients with rectal NETs of < 10 mm in diameter. The patients were randomly assigned to EMR-P and Tip-in EMR groups in a 1:1 ratio. Primary outcome was margin-negative (R0) resection rate between the two methods, with a noninferiority margin of 10%. RESULTS: Seventy-five NETs in 73 patients, including 64 eligible lesions (32 lesions in each, EMR-P and Tip-in EMR groups), were evaluated. In a modified intention-to-treat analysis, R0 resection rates of the EMR-P and Tip-in EMR groups were 96.9% and 90.6%, respectively, which did not demonstrate non-inferiority (risk difference, -6.3 [95% confidence interval: -18.0 to 5.5]). Resection time in the EMR-P group was longer than that in the Tip-in EMR group (p < 0.001). One case of intraprocedural bleeding was reported in each group. CONCLUSION: We did not demonstrate the non-inferiority of Tip-in EMR compared to EMR-P for treating small rectal NETs. However, the R0 resection rates for both techniques were high enough for clinical application.

Three-dimensional assessments are necessary to determine the true, spatially-resolved composition of tissues.

Methods for spatially resolved cellular profiling using thinly cut sections have enabled in-depth quantitative tissue mapping to study inter-sample and intra-sample differences in normal human anatomy and disease onset and progression. These methods often profile extremely limited regions, which may impact the evaluation of heterogeneity due to tissue sub-sampling. Here, we applied CODA, a deep learning-based tissue mapping platform, to reconstruct the three-dimensional (3D) microanatomy of grossly normal and cancer-containing human pancreas biospecimens obtained from individuals who underwent pancreatic resection. To compare inter- and intra-sample heterogeneity, we assessed bulk and spatially resolved tissue composition in a cohort of two-dimensional (2D) whole slide images (WSIs) and a cohort of thick slabs of pancreas tissue that were digitally reconstructed in 3D from serial sections. To demonstrate the marked under sampling of 2D assessments, we simulated the number of WSIs and tissue microarrays (TMAs) necessary to represent the compositional heterogeneity of 3D data within 10% error to reveal that tens of WSIs and hundreds of TMA cores are sometimes needed. We show that spatial correlation of different pancreatic structures decay significantly within a span of microns, demonstrating that 2D histological sections may not be representative of their neighboring tissues. In sum, we demonstrate that 3D assessments are necessary to accurately assess tissue composition in normal and abnormal specimens and in order to accurately determine neoplastic content. These results emphasize the importance of intra-sample heterogeneity in tissue mapping efforts.

Prognostic Significance of Intratumoral and Peritumoral Budding in Distal Extrahepatic Bile Duct Carcinoma.

INTRODUCTION: Although tumor budding (TB) has been recognized as a representative adverse prognosticator in gastrointestinal malignancies, it is not well-elucidated in distal extrahepatic bile duct carcinoma (DBDC). Herein, we investigated the prognostic significance of peritumoral (PTB) and intratumoral (ITB) budding according to the modified DBDC staging of the 8th edition of the American Joint Committee on Cancer. METHODS: PTB and ITB were independently evaluated in a cohort of DBDC patients (n = 410) based on the 2016 International Tumor Budding Consensus Conference (ITBCC). RESULTS: High levels of PTB (PTBHigh, ≥ grade-2) and ITB (ITBHigh, ≥ grade-3) were identified in 316 (77%) and 238 (58%) cases, respectively. In univariate analysis, PTBHigh and ITBHigh, larger size and sclerosing tumor growth pattern, higher histologic grade, extrapancreatic location, adenocarcinomas unrelated to intraductal papillary neoplasm of the bile duct (IPNB), pancreatic, duodenal, and lymphovascular invasion, perineural invasion, cancer involvement of the bile duct resection margin, nodal metastasis, and higher T and N categories and disease stages were associated with shorter patient overall survival (OS) times. In multivariate analysis, PTBHigh and ITBHigh remained poor independent prognostic indicators of OS in DBDC patients. Specifically, ITBHigh could predict poor prognosis in patients with stage I (T1N0) DBDC. CONCLUSIONS: Both PTBHigh and ITBHigh were strong prognostic indicators in patients with DBDC. Thus, ITB could be used to predict worse prognoses in patients with DBDC, in which PTB is difficult to assess, especially for patients with stage I (T1N0) DBDC.

Large Duct Pancreatic Ductal Adenocarcinoma: A Morphological Variant of Pancreatic Ductal Adenocarcinoma With Distinct CT and MRI Characteristics.

OBJECTIVE: To investigate the imaging characteristics of large duct pancreatic ductal adenocarcinoma (LD-PDAC) on computed tomography (CT) and magnetic resonance imaging (MRI). MATERIALS AND METHODS: Thirty-five patients with LD-PDAC (63.2 ± 9.7 years) were retrospectively evaluated. Tumor morphology on CT and MRI (predominantly solid mass vs. solid mass with prominent cysts vs. predominantly cystic mass) was evaluated. Additionally, the visibility, quantity, shape (oval vs. branching vs. irregular), and MRI signal intensity of neoplastic cysts within the LD-PDAC were investigated. The radiological diagnoses rendered for LD-PDAC in radiology reports were reviewed. RESULTS: LD-PDAC was more commonly observed as a solid mass with prominent cysts (45.7% [16/35] on CT and 37.1% [13/35] on MRI) or a predominantly cystic mass (20.0% [7/35] on CT and 40.0% [14/35] on MRI) and less commonly as a predominantly solid mass on CT (34.3% [12/35]) and MRI (22.9% [8/35]). The tumor morphology on imaging was significantly associated with the size of the cancer gland on histopathological examination (P = 0.020 [CT] and 0.013 [MRI]). Neoplastic cysts were visible in 88.6% (31/35) and 91.4% (32/35) of the LD-PDAC cases on CT and MRI, respectively. The cysts appeared as branching (51.6% [16/35] on CT and 59.4% [19/35] on MRI) or oval shapes (45.2% [14/35] on CT and 31.2% [10/35] on MRI) with fluid-like MRI signal intensity. In the radiology reports, 10 LD-PDAC cases (28.6%) were misinterpreted as diseases other than typical PDAC, particularly intraductal papillary mucinous neoplasms. CONCLUSION: LD-PDAC frequently appears as a solid mass with prominent cysts or as a predominantly cystic mass on CT and MRI. Radiologists should be familiar with the imaging features of LD-PDAC to avoid misdiagnosis.

Prognostic Significance of Cyclin D1 Expression in Small Intestinal Adenocarcinoma.

Cyclin D1, a critical cyclin-dependent kinase (CDK) 4/6-dependent regulator of G1/S transition, has attracted much interest as a therapeutic target. The cyclin D1 expression in small intestinal adenocarcinomas (SIACs) has not yet been comprehensively studied, owing to the rarity of this tumor. We investigated the clinicopathological and prognostic significance of the cyclin D1 expression in 232 surgically resected primary SIACs through a multi-institutional study. A high expression of cyclin D1 (cyclin D1High) was detected in 145 SIAC cases (63%), which was significantly higher than that in normal small intestinal mucosa (11%). Cyclin D1High was more commonly found in SIACs with a lower T-category and disease stage and KRAS mutation and predicted better patient survival. Multivariate analysis revealed that cyclin D1High, the absence of retroperitoneal seeding and lymphovascular invasion, and the lower N-category were identified as independent prognostic indicators for patients with SIACs. Specifically, cyclin D1High affected patient survival in the lower stage group (stages I and II). In conclusion, cyclin D1 was commonly overexpressed in SIACs, and cyclin D1High acted as a favorable prognostic indicator in patients with SIACs. These findings in SIACs may, thus, be important to further comprehend the mechanism of cyclin D1 in carcinogenesis and to strategize appropriate patient therapies.

Systematic review of challenging issues in pathology of intraductal papillary mucinous neoplasms.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMNs) are a cystic precursor to pancreatic cancer. IPMNs deemed clinically to be at high-risk for malignant progression are frequently treated with surgical resection, and pathological examination of the pancreatectomy specimen is a key component of the clinical care of IPMN patients. METHODS: Systematic literature reviews were conducted around eight topics of clinical relevance in the examination of pathological specimens in patients undergoing resection of IPMN. RESULTS: This review provides updated perspectives on morphological subtyping of IPMNs, classification of intraductal oncocytic papillary neoplasms, nomenclature for high-grade dysplasia, assessment of T stage, distinction of carcinoma associated or concomitant with IPMN, role of molecular assessment of IPMN tissue, role of intraoperative assessment by frozen section, and preoperative evaluation of cyst fluid cytology. CONCLUSIONS: This analysis provides the foundation for data-driven approaches to several challenging issues in the pathology of IPMNs.

Recurrent gastric amphicrine tumor with neuroendocrine and pancreatic acinar cell differentiation and somatic MEN1 inactivation arisen during immunotherapy.

Amphicrine neoplasms (ANs) are poorly understood epithelial malignancies composed of cells with co-existing exocrine-neuroendocrine features. Here, we report a recurrent mucin-producing gastric amphicrine tumor co-expressing neuroendocrine (chromogranin-A, synaptophysin, and CD56) and pancreatic acinar cell (BCL10 and trypsin) markers, arisen in a 64-year-old woman during adjuvant immunotherapy for melanoma. Ki-67 was < 2%. The gastric background context was atrophic gastritis. Next-generation sequencing showed MEN1 mutation (p.P71fs*42) coupled with loss of heterozygosity. The key lessons were as follows: (1) gastric ANs can show the co-existence of exocrine mucin-producing elements with neuroendocrine and pancreatic acinar differentiation; (2) they may represent a new entity arising in the context of atrophic gastritis and during immunotherapy; (3) they should be considered in the diagnostic workup of gastric neuroendocrine tumors; and (4) their molecular profile can show striking similarities with well-differentiated neuroendocrine tumors. These findings may be of help to improve the knowledge and the biological taxonomy of ANs.

Comprehensive characterisation of acinar cystic transformation of the pancreas: a systematic review.

AIMS: Acinar cystic transformation (ACT) of the pancreas is a rare pancreatic cystic lesion. Owing to its rarity, comprehensive histomolecular characterisation of this entity is still lacking. We aim to perform a systematic review on this controversial entity. METHODS: We searched PubMed, SCOPUS and Embase through May 2023 to identify all studies on ACTs. Clinicopathological, immunohistochemical (IHC) and molecular data have been extracted and analysed. RESULTS: Overall, there were 121 cases of ACTs in the literature. ACT had a female predominance (65.3% of patients), and a mean size of 4.8 cm. ACT was more often unifocal (71.9%) and multiloculate (61.2%). Histologically, the cysts were lined by an acinar epithelium, sometimes harbouring ductal-like areas (18.2%). In five cases (4.1%), an intralesional pancreatic intraepithelial neoplasia (PanIN) was reported. Preoperative diagnosis is challenging. After surgical resection, all patients were alive and disease free during follow-up except one patient who developed a second ACT after resection. By IHC, all lesions were positive for acinar markers; cytokeratin 7 and 8/18/19 were usually positive, and Ki-67 was invariably ≤3%. At the molecular level, three cases demonstrated genetic alterations: one showed multiple chromosomal gains, and other two harboured somatic mutations of KRAS and SMO genes (one mutation per case). CONCLUSIONS: Globally considered, our findings demonstrated that ACT is a benign entity, without the need of surgical resection with the exception of symptomatic lesions. The rare occurrence of intracystic PanINs and driver mutations suggest considering follow-up if a preoperative diagnosis of ACT can be made.

Human Neuralized is a novel tumour suppressor targeting Wnt/ß-catenin signalling in colon cancer.

While there is growing evidence that many epigenetically silenced genes in cancer are tumour suppressor candidates, their significance in cancer biology remains unclear. Here, we identify human Neuralized (NEURL), which acts as a novel tumour suppressor targeting oncogenic Wnt/ß-catenin signalling in human cancers. The expression of NEURL is epigenetically regulated and markedly suppressed in human colorectal cancer. We, therefore, considered NEURL to be a bona fide tumour suppressor in colorectal cancer and demonstrate that this tumour suppressive function depends on NEURL-mediated oncogenic ß-catenin degradation. We find that NEURL acts as an E3 ubiquitin ligase, interacting directly with oncogenic ß-catenin, and reducing its cytoplasmic levels in a GSK3ß- and ß-TrCP-independent manner, indicating that NEURL-ß-catenin interactions can lead to a disruption of the canonical Wnt/ß-catenin pathway. This study suggests that NEURL is a therapeutic target against human cancers and that it acts by regulating oncogenic Wnt/ß-catenin signalling.

Investigation of artificial intelligence integrated fluorescence endoscopy image analysis with indocyanine green for interpretation of precancerous lesions in colon cancer.

Indocyanine green (ICG) has been used in clinical practice for more than 40 years and its safety and preferential accumulation in tumors has been reported for various tumor types, including colon cancer. However, reports on clinical assessments of ICG-based molecular endoscopy imaging for precancerous lesions are scarce. We determined visualization ability of ICG fluorescence endoscopy in colitis-associated colon cancer using 30 lesions from an azoxymethane/dextran sulfate sodium (AOM/DSS) mouse model and 16 colon cancer patient tissue-samples. With a total of 60 images (optical, fluorescence) obtained during endoscopy observation of mouse colon cancer, we used deep learning network to predict four classes (Normal, Dysplasia, Adenoma, and Carcinoma) of colorectal cancer development. ICG could detect 100% of carcinoma, 90% of adenoma, and 57% of dysplasia, with little background signal at 30 min after injection via real-time fluorescence endoscopy. Correlation analysis with immunohistochemistry revealed a positive correlation of ICG with inducible nitric oxide synthase (iNOS; r > 0.5). Increased expression of iNOS resulted in increased levels of cellular nitric oxide in cancer cells compared to that in normal cells, which was related to the inhibition of drug efflux via the ABCB1 transporter down-regulation resulting in delayed retention of intracellular ICG. With artificial intelligence training, the accuracy of image classification into four classes using data sets, such as fluorescence, optical, and fluorescence/optical images was assessed. Fluorescence images obtained the highest accuracy (AUC of 0.8125) than optical and fluorescence/optical images (AUC of 0.75 and 0.6667, respectively). These findings highlight the clinical feasibility of ICG as a detector of precancerous lesions in real-time fluorescence endoscopy with artificial intelligence training and suggest that the mechanism of ICG retention in cancer cells is related to intracellular nitric oxide concentration.