Cancer-associated fibroblasts reuse cancer-derived lactate to maintain a fibrotic and immunosuppressive microenvironment in pancreatic cancer.

Glycolysis is highly enhanced in pancreatic ductal adenocarcinoma (PDAC) cells; thus, glucose restrictions are imposed on nontumor cells in the PDAC tumor microenvironment (TME). However, little is known about how such glucose competition alters metabolism and confers phenotypic changes in stromal cells in the TME. Here, we report that cancer-associated fibroblasts (CAFs) with restricted glucose availability utilize lactate from glycolysis-enhanced cancer cells as a fuel and exert immunosuppressive activity in the PDAC TME. The expression of lactate dehydrogenase A (LDHA), which regulates lactate production, was a poor prognostic factor for patients with PDAC, and LDHA depletion suppressed tumor growth in a CAF-rich murine PDAC model. Coculture of CAFs with PDAC cells revealed that most of the glucose was taken up by the tumor cells and that CAFs consumed lactate via monocarboxylate transporter 1 to enhance proliferation through the TCA cycle. Moreover, lactate-stimulated CAFs upregulated IL-6 expression and suppressed cytotoxic immune cell activity synergistically with lactate. Finally, the LDHA inhibitor FX11 reduced tumor growth and improved antitumor immunity in CAF-rich PDAC tumors. Our study provides insight regarding the crosstalk among tumor cells, CAFs, and immune cells mediated by lactate and offers therapeutic strategies for targeting LDHA enzymatic activity in PDAC cells.

Microsatellite Instability-high Signet Ring Cell Carcinoma of the Colon Treated With Immunotherapy: Report of a Case.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are attracting increasing attention as a novel and potentially curative therapy for microsatellite instability-high (MSI-H) colorectal cancer (CRC). CASE REPORT: An 80-year-old female visited our hospital with complaints of lower abdominal pain due to bowel obstruction caused by descending colon cancer. After 1 month of metallic stent detention, she underwent radical surgery, although laparotomy showed broad peritoneal dissemination. Based on the genetic finding of MSI-H status, pembrolizumab therapy was administered in two cycles. Unfortunately, the therapy was ineffective, and the patient died after being discharged 5 months after surgery. CONCLUSION: The findings in this case of MSI-H CRC with a poor response to an ICI suggest the importance of confirming HLA status, including beta-2-microglobulin and HLA expression, before starting ICI therapy in cases of MSI-H CRC.

Statins exert anti-growth effects by suppressing YAP/TAZ expressions via JNK signal activation and eliminate the immune suppression by downregulating PD-L1 expression in pancreatic cancer.

Statins are cholesterol-lowering agents that act as inhibitors of 3-hydroxy-3-methyl-glutaryl-coenzymeA (HMG CoA) reductase. Recently, statins have received a lot of attention, especially regarding how statins act on the immune system. Here, the clinical impact of statin intake was examined in patients with resected pancreatic cancer, and the underlying mechanisms were investigated in vitro and in vivo. We found that statin intake was associated with favorable prognostic outcomes in patients with resectable pancreatic cancer. Statins, especially lipophilic statins, exert anti-proliferative effects on pancreatic cancer cells in vitro (simvastatin > fluvastatin > atorvastatin > rosuvastatin > pravastatin). Simvastatin had an anti-proliferative effect on pancreatic cancer cells with decreased the yes-associated protein (YAP)/PDZ-binding motif (TAZ) expression by activating the JNK pathway, and simvastatin treatment with oxaliplatin revealed additive anti-growth effects. Furthermore, lipophilic and hydrophilic statins suppressed programmed cell death ligand 1 (PD-L1) expression by downregulating TAZ. Simvastatin treatment with an anti-PD-1 drug (BP0273) provided immediate anti-growth effects compared to controls, such as anti-PD-1 only and simvastatin only, and suppressed progressive disease during the early period of anti-PD-1 treatment in vivo. In conclusion, Statins display two distinct anti-cancer effects (direct anti-growth effect and elimination of immune suppression by downregulating PD-L1 expression) by targeting YAP/TAZ expression.

Biological and Clinical Impacts of Glucose Metabolism in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer type as it is prone to metastases and is difficult to diagnose at an early stage. Despite advances in molecular detection, its clinical prognosis remains poor and it is expected to become the second leading cause of cancer-related deaths. Approximately 85% of patients develop glucose metabolism disorders, most commonly diabetes mellitus, within three years prior to their pancreatic cancer diagnosis. Diabetes, or glucose metabolism disorders related to PDAC, are typically associated with insulin resistance, and beta cell damage, among other factors. From the perspective of molecular regulatory mechanisms, glucose metabolism disorders are closely related to PDAC initiation and development and to late invasion and metastasis. In particular, abnormal glucose metabolism impacts the nutritional status and prognosis of patients with PDAC. Meanwhile, preliminary research has shown that metformin and statins are effective for the prevention or treatment of malignancies; however, no such effect has been shown in clinical trials. Hence, the causes underlying these conflicting results require further exploration. This review focuses on the clinical significance of glucose metabolism disorders in PDAC and the mechanisms behind this relationship, while also summarizing therapeutic approaches that target glycolysis.

Hyperglycaemia induces metabolic reprogramming into a glycolytic phenotype and promotes epithelial-mesenchymal transitions via YAP/TAZ-Hedgehog signalling axis in pancreatic cancer.

BACKGROUND: Hyperglycaemia is a well-known initial symptom in patients with pancreatic ductal adenocarcinoma (PDAC). Metabolic reprogramming in cancer, described as the Warburg effect, can induce epithelial-mesenchymal transition (EMT). METHODS: The biological impact of hyperglycaemia on malignant behaviour in PDAC was examined by in vitro and in vivo experiments. RESULTS: Hyperglycaemia promoted EMT by inducing metabolic reprogramming into a glycolytic phenotype via yes-associated protein (YAP)/PDZ-binding motif (TAZ) overexpression, accompanied by GLUT1 overexpression and enhanced phosphorylation Akt in PDAC. In addition, hyperglycaemia enhanced chemoresistance by upregulating ABCB1 expression and triggered PDAC switch into pure basal-like subtype with activated Hedgehog pathway (GLI1 high, GATA6 low expression) through YAP/TAZ overexpression. PDAC is characterised by abundant stroma that harbours tumour-promoting properties and chemoresistance. Hyperglycaemia promotes the production of collagen fibre-related proteins (fibronectin, fibroblast activation protein, COL1A1 and COL11A1) by stimulating YAP/TAZ expression in cancer-associated fibroblasts (CAFs). Knockdown of YAP and/or TAZ or treatment with YAP/TAZ inhibitor (K975) abolished EMT, chemoresistance and a favourable tumour microenvironment even under hyperglycemic conditions in vitro and in vivo. CONCLUSION: Hyperglycaemia induces metabolic reprogramming into glycolytic phenotype and promotes EMT via YAP/TAZ-Hedgehog signalling axis, and YAP/TAZ could be a novel therapeutic target in PDAC.

Thrombospondin-1 overexpression stimulates loss of Smad4 and accelerates malignant behavior via TGF-ß signal activation in pancreatic ductal adenocarcinoma.

INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant stroma and cancer-associated fibroblasts (CAFs) provide a favorable tumor microenvironment. Smad4 is known as tumor suppressor in several types of cancers including PDAC, and loss of Smad4 triggers accelerated cell invasiveness and metastatic potential. The thrombospondin-1 (TSP-1) can act as a major activator of latent transforming growth factor-ß (TGF-ß) in vivo. However, the roles of TSP-1 and the mediator of Smad4 loss and TGF-ß signal activation during PDAC progression have not yet been addressed. The aim is to elucidate the biological role of TSP-1 in PDAC progression. METHODS AND RESULTS: High substrate stiffness stimulated TSP-1 expression in CAFs, and TSP-1 knockdown inhibited cell proliferation with suppressed profibrogenic and activated stroma-related gene expressions in CAFs. Paracrine TSP-1 treatment for PDAC cells promoted cell proliferation and epithelial mesenchymal transition (EMT) with activated TGF-ß signals such as phosphorylated Akt and Smad2/3 expressions. Surprisingly, knockdown of DPC4 (Smad4 gene) induced TSP-1 overexpression with TGF-ß signal activation in PDAC cells. Interestingly, TSP-1 overexpression also induced downregulation of Smad4 expression and enhanced cell proliferation in vitro and in vivo. Treatment with LSKL peptide, which antagonizes TSP-1-mediated latent TGF-ß activation, attenuated cell proliferation, migration and chemoresistance with enhanced apoptosis in PDAC cells. CONCLUSIONS: TSP-1 derived from CAFs stimulates loss of Smad4 expression in cancer cells and accelerates malignant behavior by TGF-ß signal activation in PDAC. TSP-1 could be a novel therapeutic target, not only for CAFs in stiff stroma, but also for cancer cells in the PDAC microenvironment.

Risk factors for lymph node metastasis in patients with pancreatic neuroendocrine neoplasms.

BACKGROUND: Although PNENs generally have a better prognosis than pancreatic cancers, some PNENs display malignant behavior including lymph node (LN) metastasis. Complete tumor resection can be the only potentially curative treatment for patients with resectable PNENs. However, the indications for LN dissection are still controversial. Over the last decade, minimally invasive surgery such as laparoscopic pancreatic surgery (LPS) has been increasingly performed for pancreatic tumors including PNENs. AIM: To investigate the risk factors for LN metastasis in PNENs and to select appropriate patients for limited surgery by LPS. METHODS: From April 2001 to December 2019, 92 patients underwent pancreatic resection for PNENs at Kumamoto University Hospital. Finally, 82 patients were enrolled in this study. Using perioperative factors, we examined the predictive factors for LN metastasis in PNENs. RESULTS: Among the 82 patients, the percentage of LN metastasis according to the pathological findings was 12% (10/82 cases). The median tumor size was 12 mm (range: 5-90 mm). The median tumor size in the LN-positive group (37 mm) was significantly larger than that in the LN-negative group (12 mm) (P = 0.0001). Multivariate analyses revealed that larger tumor size (≥ 20 mm) was an independent risk factor for LN metastasis (odds ratio 16.8, P = 0.0062). In patients with small tumors (≤ 10 mm), LN metastasis was not found. CONCLUSION: Larger tumor size (≥ 20 mm) is an independent risk factor for LN metastasis in PNENs. In smaller PNENs (≤ 10 mm), we may be able to choose limited surgery without LN dissection.

Statin as a therapeutic agent in gastroenterological cancer.

Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase, the rate-limiting enzyme of the mevalonate pathway, and are widely used as an effective and safe approach handle hypercholesterolemia. The mevalonate pathway is a vital metabolic pathway that uses acetyl-CoA to generate isoprenoids and sterols that are crucial to tumor growth and progression. Multiple studies have indicated that statins improve patient prognosis in various carcinomas. Basic research on the mechanisms underlying the antitumor effects of statins is underway. The development of new anti-cancer drugs is progressing, but increasing medical costs from drug development have become a major obstacle. Readily available, inexpensive and well-tolerated drugs like statins have not yet been successfully repurposed for cancer treatment. Identifying the cancer patients that may benefit from statins is key to improved patient treatment. This review summarizes recent advances in statin research in cancer and suggests important considerations for the clinical use of statins to improve outcomes for cancer patients.

Recent advances in artificial intelligence for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains the most lethal type of cancer. The 5-year survival rate for patients with early-stage diagnosis can be as high as 20%, suggesting that early diagnosis plays a pivotal role in the prognostic improvement of PDAC cases. In the medical field, the broad availability of biomedical data has led to the advent of the "big data" era. To overcome this deadly disease, how to fully exploit big data is a new challenge in the era of precision medicine. Artificial intelligence (AI) is the ability of a machine to learn and display intelligence to solve problems. AI can help to transform big data into clinically actionable insights more efficiently, reduce inevitable errors to improve diagnostic accuracy, and make real-time predictions. AI-based omics analyses will become the next alterative approach to overcome this poor-prognostic disease by discovering biomarkers for early detection, providing molecular/genomic subtyping, offering treatment guidance, and predicting recurrence and survival. Advances in AI may therefore improve PDAC survival outcomes in the near future. The present review mainly focuses on recent advances of AI in PDAC for clinicians. We believe that breakthroughs will soon emerge to fight this deadly disease using AI-navigated precision medicine.

Biological Significance of YAP/TAZ in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal types of cancer. Despite major advances in defining the molecular mutations driving PDAC, this disease remains universally lethal with an overall 5-year survival rate of only about 7-8%. Genetic alterations in PDAC are exemplified by four critical genes (KRAS, TP53, CDKN2A, and SMAD4) that are frequently mutated. Among these, KRAS mutation ranges from 88% to 100% in several studies. Hippo signaling is an evolutionarily conserved network that plays a key role in normal organ development and tissue regeneration. Its core consists of the serine/threonine kinases mammalian sterile 20-like kinase 1 and 2 (MST1/2) and large tumor suppressor 1 and 2. Interestingly, pancreas-specific MST1/2 double knockout mice have been reported to display a decreased pancreas mass. Many of the genes involved in the Hippo signaling pathway are recognized as tumor suppressors, while the Hippo transducers Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) are identified as oncogenes. By dephosphorylation, YAP and TAZ accumulate in the nucleus and interact with transcription factors such as TEA domain transcription factor-1, 2, 3, and 4. Dysregulation of Hippo signaling and activation of YAP/TAZ have been recognized in a variety of human solid cancers, including PDAC. Recent studies have elucidated that YAP/TAZ play a crucial role in the induction of acinar-to-ductal metaplasia, an initial step in the progression to PDAC, in genetically engineered mouse models. YAP and TAZ also play a key role in the development of PDAC by both KRAS-dependent and KRAS-independent bypass mechanisms. YAP/TAZ have become extensively studied in PDAC and their biological importance during the development and progression of PDAC has been uncovered. In this review, we summarize the biological significance of a dysregulated Hippo signaling pathway or activated YAP/TAZ in PDAC and propose a role for YAP/TAZ as a therapeutic target.

Frailty is associated with poor prognosis after resection for pancreatic cancer.

BACKGROUND: With population aging, the number of frail patients with pancreatic cancer has increased. The Clinical Frailty Scale (CFS) is a simple and validated tool to assess frailty, and higher scores predict worse clinical outcomes after cardiovascular surgery. In this retrospective study, we aimed to examine the association of preoperative frailty with prognosis after resection for pancreatic cancer. METHODS: We retrospectively analyzed data from 142 consecutive patients undergoing resection for pancreatic cancer between April 2010 and December 2018. We used the CFS: 1 (very fit) to 9 (terminally ill) to assess frailty and examined associations of the CFS scores with recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs), controlling for potential confounders. RESULTS: Of the 142 patients, 113 (80%) had CFS scores of ≤ 3, 13 (9.2%) scores of 4, and 16 (11%) scores of ≥ 5. Scores of ≥ 5 on the CFS were associated with worse CSS (univariable HR: 2.62, 95% confidence interval [CI]: 1.19-5.18, P = 0.019; multivariable HR: 2.49, 95% CI 1.05-5.34, P = 0.039) and OS (univariable HR: 2.42, 95% CI 1.19-4.46, P = 0.016; multivariable HR: 2.25, 95% CI 1.05-4.43, P = 0.038). The association between CFS scores and RFS was not significant in multivariable analysis (univariable HR: 2.11, 95% CI 1.08-3.79, P = 0.030; multivariable HR: 1.47, 95% CI 0.71-2.83, P = 0.29). CONCLUSION: Higher scores on the CFS are associated with worse CSS and OS after resection for pancreatic cancer. Preoperative measurement of frailty may improve risk assessment among patients with pancreatic cancer.

Proteomic Analysis of Malignant Ascites From Patients With Pancreatic Ductal Adenocarcinoma.

BACKGROUND/AIM: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor. Research using an innovative research approach is needed to identify effective biomarkers or therapeutic targets for PDAC. We aimed to identify proteins related to the peritoneal dissemination of PDAC. MATERIALS AND METHODS: We performed proteomic analysis using ascites samples from patients with advanced PDAC and peritoneal dissemination and patients with liver cirrhosis (LC). Proteins specific to PDAC were identified in comparison to the findings for ascites from patients with LC as a control group. RESULTS: In total, 336 proteins were identified in ascites from patients with PDAC. We identified 18 specific proteins in ascites from patients with advanced PDAC. Among these proteins, CD13, lymphatic vessel endothelial hyaluronan receptor 1, ficolin-3, and V-set and immunoglobulin domain containing 4 were the most frequently detected. In addition, these 18 proteins could be classified into four categories: extracellular matrix, immunity, metabolism, and others. CONCLUSION: The identified proteins could be informative for developing treatment strategies for patients with PDAC and peritoneal dissemination.

Successful surgical rescue of delayed onset diaphragmatic hernia following radiofrequency ablation using a thoracoscopic approach for hepatocellular carcinoma: a case report.

BACKGROUND: Radiofrequency ablation (RFA) is widely used as a minimally invasive treatment for hepatocellular carcinoma (HCC). RFA has a low risk of complications, especially compared with liver resection. Nevertheless, various complications have been reported after RFA for HCC; however, diaphragmatic hernia (DH) is extremely rare. CASE PRESENTATION: A 78-year-old man underwent thoracoscopic RFA for HCC located at the medial segment adjacent to the diaphragm approximately 7 years before being transported to the emergency department due complaints of nausea and abdominal pain. Computed tomography revealed a prolapsed small intestine through a defect in the right diaphragm, and emergency surgery was performed. The cause of diaphragmatic hernia was the scar of RFA. We confirmed that the small intestine had prolapsed into the right diaphragm, and we resected the necrotic small intestine and repaired the right diaphragm. Herein, we report a case of ileal strangulation due to diaphragmatic hernia after thoracoscopic RFA. CONCLUSIONS: Care should be taken when performing thoracoscopic RFA, especially for tumors located on the liver surface adjacent to the diaphragm. Patients should be carefully followed up for possible DH, even after a long postoperative interval.

MicroRNA-25 Exerts an Oncogenic Function by Regulating the Ubiquitin Ligase Fbxw7 in Hepatocellular Carcinoma.

BACKGROUND: MicroRNA (miRNA) expression abnormalities are implicated in tumor progression. Previous reports have indicated that microRNA-25 (miR-25) acts as a tumor suppressor or oncogene in diverse cancers. However, its molecular mechanisms in hepatocellular carcinoma (HCC) are still unclear. F-box and WD repeat domain 7 (Fbxw7) is a critical tumor suppressor and is one of the most important deregulated proteins of the ubiquitin-proteasome system in cancer. Our objective was to elucidate the role of miR-25 and Fbxw7 in HCC and to clarify the mechanism by which Fbxw7 is regulated. METHODS: Fbxw7 expression was estimated in 210 fixed paraffin-embedded HCC samples by immunohistochemistry, and miR-25 expression was evaluated in 142 frozen HCC tissue samples by quantitative real-time PCR. Oncogenic functions of miR-25 and its role in the regulation of Fbxw7 expression were assayed in vitro. RESULTS: miR-25 was overexpressed in HCC tissue compared with adjacent normal tissue and significantly correlated with a poorer prognosis. Moreover, it was inversely correlated with Fbxw7 expression in HCC tissues. Furthermore, miR-25 inhibition significantly reduced the proliferation, migration, and invasion of HCC cells in vitro. CONCLUSION: miR-25 may promote tumor progression in HCC patients by repression of Fbxw7 and could serve as a promising molecular target for HCC treatment.

Intraoperative bile culture helps choosing antibiotics in pancreaticoduodenectomy: Mechanistic profiling study of complex rink between bacterobilia and postoperative complications.

BACKGROUND: Postoperative complications after pancreaticoduodenectomy (PD) is still a major concern. The aim of this study was to propose how to choose antibiotics, based on bacterial sensitivity profiling involved in postoperative complications after PD. METHODS: Two hundred and thirty patients underwent PD between 2008 and 2018 at Kumamoto University Hospital. We enrolled 121 patients who had both intraoperative bile culture and drain culture on postoperative day (POD) 3. The clinical impact of the bacterial profile on postoperative outcome was retrospectively analyzed. RESULTS: Multivariate regression analysis revealed that intraperitoneal contamination on POD3 was independently associated with postoperative complications (odds ratio 2.62, P = .02). The bacteria in intraperitoneal drain on POD3 showed 94.9% similarity with those in bile collected during surgery. The major species were Enterococcus (44.6%) and Enterobacter (38.5%). Enterobacter species caused a higher rate of postoperative complications than others (83% vs 54%, P = .04). Three out of five Enterococcus faecium were resistant to carbapenems that were active against all Gram-negative rods. CONCLUSIONS: Intraperitoneal contamination on POD3, which had similar bacterial species as bile collected during surgery, was correlated with postoperative complications. The bacterial antibiotic sensitivity profile may help selecting optimal antibiotics against infectious postoperative complications in PD.

CD44 expression enhances chemoresistance and implies occult micrometastases after conversion hepatectomy for initially unresectable colorectal liver metastases.

AIM: The objective of this study was to examine the clinical and biological significance of CD44 expression in conversion hepatectomy for initially unresectable colorectal liver metastases. METHODS: Fifty-four patients who received chemotherapy followed by hepatectomy (conversion hepatectomy) for initially unresectable liver metastases were enrolled. CD44 expression and its clinical significance were examined in 52 resected specimens; two specimens revealed no residual cancer cells. The biological significance of CD44 expression in the chemoresistance response to fluorouracil, oxaliplatin or irinotecan, three major anti-cancer agents for colon cancer in the clinical setting, was examined using colon cancer cell lines. RESULTS: Membrane CD44 expression in the residual cancer cells after chemotherapy for colorectal liver metastases was detectable in 19 patients (37%), and was significantly associated with high proliferative activity represented by Ki-67 expression (P = 0.003). CD44 expression was also significantly associated with shorter disease-free survival and worse overall survival after hepatectomy (hazard ratio and P-values were 2.570, 0.007 and 3.457, 0.026, respectively). In SW480 and HT29 colon cancer cells, siRNA-mediated CD44 knockdown attenuated cell growth. Additionally, CD44 knockdown overcame chemoresistance in response to fluorouracil and oxaliplatin with enhanced apoptosis and p27 upregulation, respectively. For irinotecan, CD44 knockdown showed no additional effect in chemoresistance. CONCLUSIONS: CD44 enhances chemoresistance in response to anti-cancer drugs (fluorouracil and oxaliplatin) in colon cancer cells. CD44 expression in liver metastases after chemotherapy implies the presence of occult micrometastases and is a worse prognostic factor in patients with conversion hepatectomy for initially unresectable colorectal liver metastases.

Prognostic Impact of Coagulation Activity in Patients Undergoing Curative Resection for Pancreatic Ductal Adenocarcinoma.

BACKGROUND/AIM: The aim of this study was to elucidate the clinical impact of coagulation disorders on outcomes after curative resection of pancreatic ductal adenocarcinoma. PATIENTS AND METHODS: Preoperative coagulation activity in 135 patients, who had undergone curative resections for pancreatic ductal adenocarcinoma was retrospectively evaluated and the impact on survival outcomes analyzed. RESULTS: A prolonged prothrombin time-international normalized ratio (PT-INR) (≥1.1) was detected in 23/135 patients (17%). Univariate analysis that showed prolonged PT-INR was associated with worse relapse-free (hazard ratio=1.79, p=0.044) and overall (hazard ratio=2.18, p=0.004) survival. Multivariate analyses showed prolonged PT-INR, large tumor (>30 mm), and lymph node metastasis were independent predictors of poor overall survival. CONCLUSION: Prolonged PT-INR may be a predictor of poor prognosis in patients with pancreatic ductal adenocarcinoma who have undergone curative resection. Coagulation disorders may be a therapeutic target for improving outcomes of pancreatic ductal adenocarcinoma.

Multiple cholangiocarcinomas in the intrahepatic and extrahepatic biliary tree due to dichloromethane exposure: a case report.

BACKGROUND: An outbreak of cholangiocarcinoma in Japan has led to widespread concern among workers in printing plants. In March 2013, the Japanese Ministry of Health, Labour and Welfare, confirmed a causal relationship between cholangiocarcinoma and long-term exposure to dichloromethane (DCM) and 1,2-dichloropropane (DCP), which were widely used in printing plants. We herein report a rare case of successful radical resection of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts caused by past exposure to DCM. CASE PRESENTATION: A 54-year-old man developed brown urine 22 years after his last exposure to DCP and DCM. He had an 11-year history of working at a printing plant from the age of 21 to 31 years and dealt with organic solvents during his employment. Enhanced computed tomography revealed a thickened distal bile duct wall with upstream biliary dilatation and multiple intrahepatic cholangiocarcinomas located in liver segments III, VI, and VIII. Biopsy of the distal bile duct wall revealed adenocarcinoma, and a diagnosis of distal cholangiocarcinoma was made. Tumor marker levels were within the reference range (carcinoembryonic antigen, 3.3 ng/mL; carbohydrate antigen 19-9, 25.4 U/mL; SPAN-1, 13 U/mL; and DUPAN-2, 33 U/mL). The multiple intrahepatic and extrahepatic bile duct cancers were treated by subtotal stomach-preserving pancreatoduodenectomy and partial hepatectomy of segments III, VI, and VIII. Pathological examination of the surgical specimens revealed multiple cholangiocarcinomas with well-differentiated adenocarcinoma in the biliary tree. The patient was still alive without recurrence 17 months after the operation. CONCLUSIONS: We experienced a rare case of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts that developed 22 years after the patient's last exposure to DCP and DCM. Long-term and careful follow-up is required for workers with an occupational history of exposure to organic solvents because of the risk of development of cholangiocarcinoma.

Coexisting schwannoma of the gallbladder and sarcoidosis: a case report.

BACKGROUND: Schwannomas originate from Schwann cells, which are constituents of peripheral nerve sheaths, and can occur anywhere in the body at any age. Most occur in soft tissues such as subcutaneous tissues and muscles, occurrence in the abdominal cavity being relatively rare. In particular, schwannomas of the gallbladder are extremely rare. We herein report a rare case of a schwannoma that coexisted with systemic sarcoidosis and presented as a steroid-resistant mass in the gallbladder wall. CASE PRESENTATION: A 40-year-old woman was found to have thickening of the gallbladder wall during a routine medical examination and was referred to our hospital, where she was found to have granular shadows in the lungs; mediastinal, cervical, intraperitoneal, and inguinal lymphadenopathy; parotid gland enlargement; and an erythematous skin rash. She was diagnosed as having systemic sarcoidosis by transbronchial lung biopsy and bronchoalveolar lavage. All her systemic mass lesions except for the one in the gallbladder resolved or became smaller with steroid treatment. The steroid-resistant gallbladder lesion showed enhancement on contrast-enhanced computed tomography and was shown by endoscopic ultrasonography to be a 30-mm-diameter gallbladder wall lesion. We performed laparoscopic cholecystectomy, which resulted in diagnosis of the steroid-resistant tumor as a schwannoma. Five months after surgery, the patient's prednisolone dosage had been gradually reduced to 5 mg/day and she was doing well with no evidence of recurrence. CONCLUSION: Resection of a steroid-resistant tumor resulted in diagnosis of schwannoma, enabling reduction in the patient's steroid dosage for sarcoidosis.