Revealing the role of early peripancreatic bacterial contamination and Enterococcus faecalis in pancreatic fistula development after pancreaticoduodenectomy: Implications for useful antibiotic prophylaxis-An observational cohort study.

BACKGROUND: Peripancreatic bacterial contamination (PBC) is a critical factor contributing to the development of clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD). Controlling pathogenic bacteria is essential in preventing CR-POPF; however, the precise relationship between specific bacteria and CR-POPF remains unclear. This study aimed to investigate the relationship between PBC and CR-POPF after PD, with a focus on identifying potentially causative bacteria. METHODS: This prospective observational study enrolled 370 patients who underwent PD. Microbial cultures were routinely collected from peripancreatic drain fluid on postoperative days (PODs) 1, 3, and 6. Predictive factors for CR-POPF and the bacteria involved in PBC were investigated. RESULTS: CR-POPF occurred in 86 (23.2%) patients. In multivariate analysis, PBC on POD1 (Odds ratio [OR] = 3.59; P = 0.005) was one of the main independent predictive factors for CR-POPF, while prophylactic use of antibiotics other than piperacillin/tazobactam independently influenced PBC on POD1 (OR = 2.95; P = 0.010). Notably, Enterococcus spp., particularly Enterococcus faecalis, were significantly isolated from PBC in patients with CR-POPF compared to those without CR-POPF on PODs 1 and 3 (P < 0.001), and they displayed high resistance to all cephalosporins. CONCLUSIONS: Early PBC plays a pivotal role in the development of CR-POPF following PD. Prophylactic antibiotic administration, specifically targeting Enterococcus faecalis, may effectively mitigate early PBC and subsequently reduce the risk of CR-POPF. This research sheds light on the importance of bacterial control strategies in preventing CR-POPF after PD.

ß-Catenin-activated inflammatory hepatocellular adenoma with pigmentation and atypical features: a case report.

Hepatocellular adenomas are rare diseases, defined as benign liver neoplasms composed of cells with hepatocellular differentiation. Differential diagnosis of hepatocellular adenoma from other lesions, including focal nodular hyperplasia and hepatocellular carcinoma, is crucial to determine treatment strategy. We describe a case of ß-catenin-activated inflammatory hepatocellular adenoma with malignant transformation. A 50-year-old man with a suspected liver tumor, based on abdominal ultrasonography findings, was referred to our hospital. Contrast-enhanced computed tomography and magnetic resonance imaging revealed a liver tumor in S2 which was enhanced in the arterial phase to the delayed phase. Based on diagnostic imaging findings, hepatocellular adenoma or focal nodular hyperplasia was suspected. We considered the possibility of malignant potential because of the enlargement of the lesion. Thus, we performed a laparoscopic hepatectomy. Histological examination showed pigment deposition in the hepatocytes, which was determined to be lipofuscin. Mild nuclear swelling and atypia in the tumor area indicated nodular growth. Based on the histological and immunohistochemical findings, the diagnosis was ꞵ-catenin-activated inflammatory hepatocellular adenoma with atypical features. The imaging features of hepatocellular adenoma and focal nodular hyperplasia are similar, but if the tumor tends to grow, surgical treatment should be performed because of the possibility of malignant hepatocellular adenoma.

Conversion surgery following gemcitabine plus cisplatin therapy for initially unresectable gallbladder cancer with peritoneal carcinomatosis: a case report.

BACKGROUND: Conversion surgery, which is defined as chemotherapy or chemoradiotherapy followed by radical surgery, may improve survival of patients with initially unresectable advanced biliary tract cancer, including gallbladder cancer. However, there are few reports on conversion surgery for advanced gallbladder cancer. CASE PRESENTATION: A 69-year-old woman was referred to our hospital with initially unresectable gallbladder cancer with peritoneal carcinomatosis. She underwent gemcitabine plus cisplatin therapy for 9 months. Extended cholecystectomy, resection of the extrahepatic bile duct with regional lymph node dissection, and total omentectomy were then performed as conversion surgery. The patient has survived without recurrence for 19 months postoperatively (31 months after the initial diagnosis) while continuing chemotherapy. CONCLUSIONS: This case suggests that conversion surgery for advanced gallbladder cancer is effective and may be curative for locally advanced disease and distant metastasis such as peritoneal carcinomatosis.

The Cell Line-Dependent Diversity in Initial Morphological Dynamics of Pancreatic Cancer Cell Peritoneal Metastasis Visualized by an Artificial Human Peritoneal Model.

BACKGROUND: Pancreatic ductal adenocarcinoma is considered as one of the most malignant types of cancer with rapid metastasis and invasion of the cancer cells, having peritoneal metastasis (PM) as a dominant factor of poor prognosis. Although the prevention of peritoneal dissemination would result in the inhibition of the initial metastatic process and contribute in improving the poor prognosis of the pancreatic cancer, the initial dynamics of PM are still unclear because of the lack of adequate models in studying the morphological and molecular details of pancreatic cancer cells. MATERIALS AND METHODS: The artificial human peritoneal tissue (AHPT) that can be applied in studying for the spatial dynamics of cancer PM in vitro has been established previously. In this study, the initial dynamics of the three pancreatic cell lines, undifferentiated carcinoma MIA PaCa-2, poorly differentiated adenocarcinoma Panc-1, and moderately differentiated adenocarcinoma BxPC3 on AHPT are examined. RESULTS: In a morphological analysis using light and electron microscopy, MIA PaCa-2 cells spread on the mesothelial layer with disruption of the sheet structure and infiltrated into the stroma-like tissue in AHPT. On the other hand, BxPC3 cells changed shapes from round into flat ones with rapid proliferation and formed sheet structure at the surface of the tissue replacing the mesothelial layer without vertical invasion into the tissue. Panc-1 cells demonstrated the intermediate characteristics of MIA PaCa-2 and BxPC3 on AHPT. These diverse morphological characteristics were verified by the correspondence with the results in a mouse model and were reflected by the profile of secreted oncogenic proteins of the three pancreatic cell lines. CONCLUSIONS: The initial dynamics in the peritoneal dissemination of these pancreatic cancer cell lines were demonstrated by AHPT, showing the morphological and molecular diversity depending on the degree of differentiation or the properties of oncogenic protein secretion.

[A Case of Non-Resectable Pancreatic Cancer with Multiple Hepatic Metastases Treated with FOLFIRINOX Therapy and Conversion Surgery].

A 50-year-old woman was diagnosed as having pancreatic head cancer with multiple hepatic metastases. FOLFIRINOX therapy was initiated. After completing 18 courses of therapy, partial remission(PR)was achieved based on images, and surgery was then planed. The subtotal stomach-preserving pancreaticoduodenectomy and hepatic S7 partial resection were performed. Macroscopically, complete resection was achieved. Regarding pathological findings of the primary lesion and hepatic metastatic lesions, fibrous formation and hyalinizing condition induced by chemotherapy were noted; moreover, complete disappearance of cancer cells was detected. However, metastasis of poorly differentiated adenocarcinoma was detected in 12b lymph node tissue. One month after the surgery, postoperative adjunctive chemotherapy with S-1 was initiated. However, new hepatic metastasis was detected 3 months after the surgery. Although recurrence treatment was initiated, the disease progressed, and the patient died 11 months after the surgery.

Construction of artificial human peritoneal tissue by cell-accumulation technique and its application for visualizing morphological dynamics of cancer peritoneal metastasis.

Human peritoneum is composed of mesothelial monolayer and stromal tissue containing microvasculature. Dissemination and infiltration of cancer cells to the peritoneum result in cancer peritoneal metastasis which is an important prognostic factor of intraperitoneal or intrapelvic carcinoma. To elucidate an initial metastatic mechanism of cancer cells, in vitro human peritoneal models are demanded. In this study, we created a three-dimensional artificial human peritoneal tissue (AHPT) harboring the blood or lymphatic vascular network by cell-accumulation technique. Morphological analysis demonstrated that AHPT had mesothelial monolayer with polygonal flat cells with apical microvilli, and stroma-like structure containing fibroblasts surrounded by extracellular matrix and blood or lymphatic vascular network. To assess AHPT as a tool for cancer peritoneal metastasis model, colon and ovarian cancer cells (HT-29 and SKOV3) were seeded onto AHPT. HT-29 cells showed poor metastatic characteristics forming thick clusters in mesothelial layer without invasion into stroma-like structure. On the other hand, SKOV3 cells rapidly invaded intercellular spaces between mesothelial cells and then spread over the stroma-like structure accompanying lymphatic invasion, showing aggressive metastatic characteristics. These results demonstrated that the metastatic dynamics of cancer cells with different characteristics are able to visualized by AHPT, suggesting that this tissue can be a powerful tool for the basic research of cancer peritoneal dissemination and metastasis.

Microanatomical profiles on the lymphatic system in the human ampulla of Vater (immunohistochemistry and scanning electron microscopy).

BACKGROUND: Little information is available regarding microanatomy of lymphatic system in the ampulla of Vater, though it is of critical importance for an understanding of tumor progression via the lymphatics and determination of surgical strategy. The present study, therefore, aimed to demonstrate the distribution and microanatomical profiles on the lymphatic system in the ampulla. METHODS: The fine distribution and structure of the lymphatic vessels were investigated in the ampulla and the stomach by immunohistochemistry for lymphatic- (D2-40) and blood vascular- (CD31) specific markers and scanning electron microscopy. The densities of lymphatic and blood vessels were also compared. RESULTS: The duodenal papilla densely developed the lymphatics with distinct aspects of lymphatic capillaries, together with blood vessels. The density of lymphatic capillaries in the extramuscular layer in the ampulla was higher than those of both the other ampullary layers and the gastric extramuscular (subserosal) layer. CONCLUSIONS: The ampulla of Vater showed widespread lymphatic capillaries throughout the entire wall. The specific vascular system is suited to produce lymph everywhere and drain without via such a large vessel as lymphatic collector. This suggests that tumor cells invade the lymphatics and metastasize more easily in the ampulla than in the other gastrointestinal regions.

Living donor liver transplantation in a pediatric patient with preexisting yolk sac tumor.

There is ongoing discussion regarding the indications and timing of LT for patients with a preexisting extrahepatic malignancy. We herein report a pediatric case that underwent LDLT after therapy for YST. The patient, a 13-year-old female with biliary atresia, had undergone portoenterostomy at 2 months of age. She developed a left ovarian tumor with a high serum alpha-fetoprotein concentration at 10 years of age. She underwent left oophorectomy and was diagnosed with ovarian YST (Stage I). After surgery, hepatopulmonary syndrome progressed gradually. She was examined carefully and exhibited no findings to suggest the recurrence of YST. We decided to perform LDLT at 3 years and 6 months of age after the surgery for YST. The patient is currently alive and doing well without recurrence of YST at approximately 2 years after transplantation. There is no significant difference between the recurrence rate of preexisting extrahepatic malignancy and the incidence of de novo malignancy if specific cases are selected. The indications and period from surgery for preexisting extrahepatic malignancy to LT should thus be determined according to the type and stage of cancer.

[A Case of Pathological Complete Response after Neoadjuvant Chemotherapy(S-1 plus Oxaliplatin)and Laparoscopic Low Anterior Resection for Rectal Cancer].

We report a case of pathological complete response after neoadjuvant chemotherapy(NAC)(S-1 plus oxaliplatin)for rectal cancer. The patient was a 50-year-old man who had type 3 circumferential rectal cancer. An abdominal CT scan revealed locally advanced rectal cancer(cT3N2H0P0M0, cStage III b)with severe stenosis and oral-side intestinal dilatation. The patient was treated with NAC after loop-ileostomy. After 3 courses of chemotherapy, a CT scan revealed significant tumor reduction. Laparoscopic low anterior resection and bilateral lymph node dissection were performed 5 weeks after the last course of chemotherapy. The pathological diagnosis was a pathological complete response(no residual cancer cells). This case suggests that laparoscopic low anterior resection after NAC with S-1 plus oxaliplatin for locally advanced rectal cancer is a potentially effective procedure.