[Gallbladder carcinosarcoma associated with pancreaticobiliary maljunction with biliary dilation:a case report].

A 68-year-old female patient was referred to our hospital with acute cholangitis. Computed tomography revealed common bile duct dilatation, gallbladder fundal tumor, and gallbladder wall thickening attached to the tumor. Cholangiography revealed pancreaticobiliary maljunction with biliary dilation. The patient was diagnosed with pancreaticobiliary maljunction with biliary dilation and gallbladder cancer and underwent liver S4b+5 and bile duct resection and reconstruction. Pathological results revealed that the gallbladder fundal tumor included sarcoma, and the gallbladder wall thickening had adenocarcinoma;thus, the patient was diagnosed with gallbladder carcinosarcoma.

Analysis of external pressure on the left calf in the Lloyd-Davies position during colorectal surgery.

PURPOSE: Well-leg compartment syndrome (WLCS) is a potentially life-threatening postoperative complication related to the Lloyd-Davies surgical position, which can place increased external pressure on the calf region. We conducted this study to analyze external pressure changes, by applying a leg holder system to the left calf region of patients placed in the Lloyd-Davies position during laparoscopic surgery. METHODS: The study participants were 50 patients who underwent laparoscopic surgery for colorectal cancer in the Lloyd-Davies position. We assessed the maximum external pressure (MEP) on the left calf region using a pressure-distribution measurement system. Intraoperative measurements were taken continuously, and the MEP was evaluated with the patient horizontal and every 30 min during surgery in the head and right-down tilt position. RESULTS: The intraoperative MEP increased gradually when the patient was in the head and right-down tilt position and decreased when the patient was returned to the horizontal position. The MEP was higher in patients aged < 60 years, those who were obese, and those with a thick calf circumference. Both body mass index (BMI) and the maximum left calf circumference (MLCC) were found to correlate with the MEP. CONCLUSIONS: In addition to a high BMI, which is a well-known risk factor for WLCS, a high MLCC should be considered another risk factor, especially for patients under 60 years.

The cholinesterase and C-reactive protein score is a potential predictor of pseudoaneurysm formation after pancreaticoduodenectomy in patients with soft pancreas.

BACKGROUND: Pseudoaneurysm (PA) rupture after pancreaticoduodenectomy (PD) is a life-threatening complication. Most PA cases originate from postoperative pancreatic fistulas (POPFs). Although several risk factors for POPF have been identified, specific risk factors for PA formation remain unclear. Therefore, we retrospectively analyzed PD cases with soft pancreas and proposed a novel strategy for early detection of PA formation. METHODS: Overall, 120 patients underwent PD between 2010 and 2020 at our institution; of these, 65 patients with soft pancreas were enrolled. We evaluated the clinicopathological factors influencing PA formation and developed a risk score to predict PA formation. RESULTS: In total, 11 of the 65 patients developed PAs (PA formation group: PAG), and 8 of these 11 PAs ruptured. The median time to PA formation was 15 days, with a minimum of 5 days. The PAG was significantly older than the non-PA formation group, were predominantly men, and had comorbid diabetes mellitus. Pre- and intra-operative findings were similar between the two groups. Importantly, no significant differences were found in postoperative drain amylase levels and total drain amylase content. Cholinesterase and C-reactive protein (CRP) levels on postoperative day (POD) 3 were significantly different between the two groups. Multivariate analysis showed that cholinesterase ≤ 112 U/L and CRP ≥ 16.0 mg/dl on POD 3 were independent predictors of PA formation. CONCLUSIONS: Decreased cholinesterase and elevated CRP on POD 3 (Cho-C score) are useful predictors of PA formation in cases with soft pancreas. In such cases, periodic computed tomography evaluations and strict drain management are necessary to prevent life-threatening hemorrhage.

Comparison of operative outcomes between monopolar and bipolar coagulation in hepatectomy: a propensity score-matched analysis in a single center.

BACKGROUND: Various hemostatic devices have been utilized to reduce blood loss during hepatectomy. Nonetheless, a comparison between monopolar and bipolar coagulation, particularly their usefulness or inferiority, has been poorly documented. The aim of this study is to reveal the characteristics of these hemostatic devices. METHODS: A total of 264 patients who underwent open hepatectomy at our institution from January 2009 to December 2018 were included. Monopolar and bipolar hemostatic devices were used in 160 (monopolar group) and 104 (bipolar group) cases, respectively. Operative outcomes and thermal damage to the resected specimens were compared between these groups using propensity score matching according to background factors. Multivariate logistic regression analysis was performed to identify predictive factors for postoperative complications. RESULTS: After propensity score matching, 73 patients per group were enrolled. The monopolar group had significantly lower total operative time (239 vs. 275 min; P = 0.013) and intraoperative blood loss (487 vs. 790 mL; P < 0.001). However, the incidence rates of ascites (27.4% vs. 8.2%; P = 0.002) and grade ≥ 3 intra-abdominal infection (12.3% vs. 2.7%; P = 0.028) were significantly higher in the monopolar group. Thermal damage to the resected specimens was significantly longer in the monopolar group (4.6 vs. 1.2 mm; P < 0.001). Use of monopolar hemostatic device was an independent risk factor for ascites (odds ratio, 5.626, 95% confidence interval 1.881-16.827; P = 0.002) and severe intra-abdominal infection (odds ratio, 5.905, 95% confidence interval 1.096-31.825; P = 0.039). CONCLUSIONS: Although monopolar devices have an excellent hemostatic ability, they might damage the remnant liver. The use of monopolar devices can be one of the factors that increase the frequency of complications.

Emergency appendectomy versus elective appendectomy following conservative treatment for acute appendicitis: a multicenter retrospective clinical study by the Japanese Society for Abdominal Emergency Medicine.

PURPOSE: To establish the best treatment strategy for acute appendicitis. METHODS: We collected data on 2142 appendectomies performed in 2017 and compared the backgrounds and surgical outcomes of patients who underwent early surgery (ES) (< 48 h) with those managed with non-ES (> 48 h). We performed a risk factor analysis to predict postoperative complications and subgroup analysis to propose a standard treatment strategy. RESULTS: The incidence of postoperative complications was significantly higher in the ES group than in the non-ES group, and significantly lower in the laparoscopic surgery group than in the laparotomy group. Surgical outcomes, including the incidence of postoperative complications, were comparable after acute surgery (< 12 h) and subacute surgery (12-48 h), following antibiotic treatment. The risk factors for postoperative complications in the ES group were a higher age, history of abdominal surgery, perforation, high C-reactive protein level, histological evidence of gangrenous or perforated appendicitis, a long operation time, and intraoperative complications. The risk factors for postoperative complications in the non-ES group were perforation and unsuccessful conservative treatment. CONCLUSIONS: Non-early appendectomy is feasible for acute appendicitis but should be applied with care in patients with risk factors for postoperative complications or failure of pretreatment, including diabetes mellitus, abscess formation, and perforation.

Comprehensive evaluation of three-dimensional anatomy of perigastric vessels using enhanced multidetector-row computed tomography.

BACKGROUND: To perform laparoscopic gastrectomy safely, we aimed to comprehensively re-evaluate perigastric vessel anatomies using a three-dimensional angiography reconstructed from enhanced multidetector-row computed tomography data. METHODS: Perigastric vessel anatomy was preoperatively analyzed using a multidetector-row computed tomography-based three-dimensional angiography reconstructed in 127 patients undergoing gastric surgery. RESULTS: Of the 67 left gastric veins that ran along the dorsal side of the arteries, 59 (88.1%) ran along the dorsal side of the common hepatic artery and flowed into the portal vein. In 18 cases, a common trunk of one to three left gastric arteries and the replaced left hepatic artery was observed. The left inferior phrenic artery ramified from the left gastric artery in 5.5% of the cases. The right gastric artery was classified into distal (73.2%), caudal (18.1%), and proximal (8.7%) types. The infra-pyloric artery was also classified into distal (64.6%), caudal (26.0%), and proximal (9.4%) types. The posterior gastric artery branched as a common trunk with the superior polar artery in the proximal (37.9%) and distal (18.4%) regions of the splenic artery. The left gastroepiploic artery ramified from the splenic (18.1%) and inferior terminal arteries (81.9%). No, one, and two gastric branches of the left gastroepiploic artery, which ramified between the roots of the left gastroepiploic artery and its omental branch, were found in 36.5%, 49.2%, and 14.3% of the cases, respectively. CONCLUSIONS: Preoperative 3D angiography is useful for the precise evaluation of perigastric vessel anatomies, and may help us to perform laparoscopic gastrectomy and robotic surgery safely.

Body weight loss after surgery affects the continuity of adjuvant chemotherapy for pancreatic cancer.

BACKGROUND: Postoperative chemotherapy is beneficial for many pancreatic cancer patients. However, some patients require dose reduction or the discontinuation of adjuvant chemotherapy because of adverse treatment-related effects. In this study, we aimed to evaluate two main outcomes. First, we evaluated the clinicopathological factors affecting patient disease-free survival (DFS) and overall survival (OS) following upfront surgery. Second, we evaluated the factors that influence the continuity of adjuvant chemotherapy. METHODS: Fifty-four patients with resected pancreatic cancer were enrolled. First, we evaluated the clinicopathological factors affecting postoperative survival using the Kaplan-Meier method and Cox regression method. Next, factors affecting the continuity of adjuvant chemotherapy were analyzed using multiple logistic regression analysis. RESULTS: Univariate and multivariate analyses revealed that positive LN metastasis (HR (95% CI) 6.329 (2.381-16.95); p < 0.001) and relative dose intensity (RDI) < 80% for adjuvant chemotherapy (HR (95% CI) 5.154 (1.761-15.15); p = 0.003) were independent predictive factors for DFS. Regarding OS, extended dissection of the nerve plexus around the superior mesenteric artery (SMA) (HR (95% CI) 4.504 (1.721-11.76); p = 0.002), positive microscopic surgical margin (HR (95% CI) 5.565 (1.724-17.96); p = 0.004), and adjuvant chemotherapy of RDI < 80% (HR (95% CI) 3.534 (1.135-2.667); p = 0.029) were also independent predictive factors. Moreover, the level of RDI significantly correlated with DFS and OS. Multiple logistic regression analysis revealed that low RDI was significantly associated with postoperative body weight loss (BWL) ≥ 10%. CONCLUSIONS: The following factors were significantly associated with poor survival: extended dissection of the nerve plexus around the SMA, lymph node metastasis, residual tumor, and RDI of the adjuvant chemotherapy. Patient's prognosis with adjuvant chemotherapy of RDI < 80% was worse. BWL ≥10% was the most important factor affecting the continuity of adjuvant chemotherapy. Perioperative nutritional intervention is necessary for patients who receive adjuvant chemotherapy for advanced pancreatic cancer.

Decompressive laparotomy for abdominal compartment syndrome resulting from severe acute pancreatitis: a case report.

BACKGROUND: Abdominal compartment syndrome (ACS) is associated with mortality in patients with critical illness such as severe acute pancreatitis, but it remains unclear whether decompressive laparotomy for ACS can improve the prognosis of patients. CASE PRESENTATION: A woman in her 60s visited our hospital because of upper abdominal pain. On the basis of her laboratory data and abdominal contrast-enhanced computed tomography findings, acute gallstone pancreatitis was diagnosed. She underwent endoscopic sphincterotomy for the removal of the common bile duct stone. Then, a drainage tube was placed in the bile duct. However, on the 5th hospital day, her intra-abdominal pressure increased to 22 mmHg and renal dysfunction was observed, which led to the diagnosis of ACS. As intensive medical treatments did not improve her ACS, she underwent decompressive laparotomy on the 9th hospital day. Postoperatively, her laboratory data and intravesical pressure improved, and she was discharged from the hospital after abdominal closure, continuous drainage, and antibiotic therapy. CONCLUSION: As the effectiveness of decompressive laparotomy for ACS has not been established, this treatment indication remains controversial. Decompressive laparotomy is considered useful for the management of ACS, if it is performed at an appropriate time, as in the present case.

[Simultaneous occurrence of an ampullary neuroendocrine tumor and multiple duodenal/jejunal gastrointestinal stromal tumors in a patient with neurofibromatosis type 1].

A 60-year-old female visited our hospital because of the identification of two duodenal tumors on upper gastrointestinal endoscopy performed for the investigation of anemia. The oral ampullary tumor was proven to be a neuroendocrine tumor (NET) on endoscopic biopsy. However, biopsy was not performed for the anal submucosal tumor (SMT) in the third duodenal portion because the tumor was included in the planned resection area. Multiple dermal soft tumors and café-au-lait spots were noted;her mother and daughter showed the same symptoms. The patient was diagnosed with neurofibromatosis type 1 (NF1). Laparotomy revealed more than 10 nodules at the serosal surface of the duodenum and proximal jejunum. Pancreaticoduodenectomy was performed with an additional 30-cm length of the jejunum that included most of the protruding tumors. Pathologically, the ampullary tumor and the other duodenal/jejunal SMTs were NET G2 and gastrointestinal stromal tumors (GISTs), respectively. Here, we report the rare case of simultaneous occurrence of an ampullary NET and multiple duodenal/jejunal GISTs in a patient with NF1.

Role of caveolin-1 in hepatocellular carcinoma arising from non-alcoholic fatty liver disease.

The molecular features of hepatocellular carcinoma arising from non-alcoholic fatty liver disease (NAFLD-HCC) are not well known. In this study, we investigated the mechanism by which NAFLD-HCC survives in a fat-rich environment. We found that caveolin (CAV)-1 was overexpressed in clinical specimens from NAFLD-HCC patients. HepG2, HLE, and HuH-7 HCC cell lines showed decreased proliferation in the presence of the saturated fatty acids palmitic acid and stearic acid, although only HLE cells expressed high levels of CAV-1. HLE cells treated with oleic acid (OA) showed robust proliferation, whereas CAV-null HepG2 cells showed reduced proliferation and increased apoptosis. CAV-1 knockdown in HLE cells attenuated the OA-induced increase in proliferation and enhanced apoptosis. Liquid chromatography-tandem mass spectrometry analysis revealed that the levels of OA-containing ceramide, a pro-apoptotic factor, were higher in HepG2 and CAV-1-deficient HLE cells than in HLE cells, suggesting that CAV-1 inhibits apoptosis by decreasing the level of OA-containing ceramide. These results indicate that CAV-1 is important for NAFLD-HCC survival in fatty acid-rich environments and is a potential therapeutic target.

Stearate-to-palmitate ratio modulates endoplasmic reticulum stress and cell apoptosis in non-B non-C hepatoma cells.

The increased prevalence of hepatocellular carcinoma (HCC) without viral infection, namely, NHCC, is a major public health issue worldwide. NHCC is frequently derived from non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis, which exhibit dysregulated fatty acid (FA) metabolism. This raises the possibility that NHCC evolves intracellular machineries to adapt to dysregulated FA metabolism. We herein aim to identify NHCC-specifically altered FA and key molecules to achieve the adaptation. To analyze FA, imaging mass spectrometry (IMS) was performed on 15 HCC specimens. The composition of saturated FA (SFA) in NHCC was altered from that in typical HCC. The stearate-to-palmitate ratio (SPR) was significantly increased in NHCC. Associated with the SPR increase, the ELOVL6 protein level was upregulated in NHCC. The knockdown of ELOVL6 reduced SPR, and enhanced endoplasmic reticulum stress, inducing apoptosis of Huh7 and HepG2 cells. In conclusion, NHCC appears to adapt to an FA-rich environment by modulating SPR through ELOVL6.

[Spontaneous regression of pancreatic arteriovenous malformation under the influence of severe acute pancreatitis: a case report].

A 49-year-old man was diagnosed with severe acute pancreatitis because of pancreatic arteriovenous malformation (AVM). The pancreatic AVM spontaneously regressed during conservative treatment for severe acute pancreatitis. Transarterial embolization of an aneurysm in an artery branch flowing into the pancreatic AVM was performed using metallic coils, following amelioration of severe acute pancreatitis. The complete elimination of the pancreatic AVM was confirmed 1 year after embolization, and the patient has had no recurrence of pancreatic AVM and pancreatitis for over 6 years. Most cases of pancreatic AVMs with acute pancreatitis require surgical resection. This is a rare case in which the pancreatic AVM spontaneously regressed under the influence of acute severe pancreatitis.

Expression of indocyanine green-related transporters in hepatocellular carcinoma.

BACKGROUND: Indocyanine green (ICG), an organic anion used in liver function tests, is known to accumulate in hepatocellular carcinoma (HCC) tissues after an intravenous injection. Because the intratumoral expression of transporters for chemical agents influences the behaviors of some malignant tumors, we investigated whether the expression of ICG-related transporters influenced the clinicopathologic features of HCC. MATERIALS AND METHODS: ICG accumulation patterns were examined using near-infrared spectroscopy and the protein expression of ICG-related transporters was assessed using immunohistochemistry and immunoblotting in 40 resected HCC specimens. We also determined whether the intratumor expression of these transporters affected intratumor lipid composition by imaging mass spectrometry. RESULTS: Immunoblot analysis revealed that the expression of organic anion transporting polypeptide 1B3 (OATP1B3) and multidrug resistance p-glycoprotein (MDR)-3, as influx and efflux transporters, respectively, were significantly higher in ICG-accumulated HCC (ICG-high HCC) than in ICG-low HCC. ICG was fluorescently observed in the pseudoglands and bile canaliculi abundantly expressing MDR3. An immunohistochemical examination revealed significantly worse disease-free and overall survival rates in patients with MDR3-negative HCC, in which the intratumoral accumulation of some phosphatidylcholine species was observed under imaging mass spectrometry. CONCLUSIONS: The intratumoral expression of MDR3, a key efflux transporter of ICG, affected the prognosis of patients with HCC, presumably by altering the lipid composition of the lipid bilayers.

Macrophage density and macrophage colony-stimulating factor expression predict the postoperative prognosis in patients with intrahepatic cholangiocarcinoma.

PURPOSES: Macrophages are included in the stromal compartments in various neoplasms, and their behavior against tumors is diverse. The aim of this study was to examine the role of tumor-infiltrating macrophages and their main regulator, macrophage colony-stimulating factor (M-CSF), in intrahepatic cholangiocarcinoma (ICC). METHODS: Macrophage density and M-CSF expression in 39 resected ICC specimens were immunohistochemically evaluated in the central and peripheral areas of tumors, which were defined as fields more than and within 500 µm from the invasive front, respectively. The number of CD68-positive macrophages was counted using an image-analyzing software program. The relationship between these results and other clinicopathological factors and the postoperative prognosis were evaluated. RESULTS: Sporadic M-CSF expression in cancer cells around the peripheral area was observed in fourteen patients. M-CSF-positive ICCs showed a higher macrophage density in the tumor-peripheral area than did M-CSF-negative ICCs. M-CSF expression and higher macrophage density in the tumor-peripheral area were related to a better postoperative prognosis, whereas a higher macrophage density in the central area was one of the significant risk factors for a poor prognosis in a univariate analysis. CONCLUSION: Tumor-peripheral macrophage infiltration, presumably dependent on M-CSF, and M-CSF-independent tumor-central macrophage infiltration are predictive factors for better and worse postoperative prognosis in ICC patients, respectively. The tumor microenvironment, such as the presence of hypoxia, may affect the behavior of infiltrating macrophages in ICC.

Pancreatic metastases of cerebellar hemangiopericytoma occurring 24 years after initial presentation: report of a case.

Hemangiopericytoma (HPC) preferentially developing in soft tissues and the meninges has been gradually recognized to be an aggressive, highly metastatic tumor. We herein report the case of a 65-year-old male with pancreatic metastases of cerebellar HPC that developed following two resections of intracranial local recurrent foci, 24 years after the initial craniotomy and 7 years after resection of metastases to the lungs and kidneys. Follow-up abdominal computed tomography scanning and magnetic resonance imaging revealed a solitary tumor in the pancreatic body. Since no other recurrent foci were detectable, distal pancreatectomy was performed. Another metastasis was incidentally found in the resected pancreas. Both foci were pathologically proven to be metastases of HPC. Among the 12 reported cases of pancreatic metastases of HPC, including ours, this case showed the longest duration between initial onset and the development of pancreatic metastases, suggesting that providing long-term follow-up is necessary for HPC patients.

Detection of intrahepatic veno-venous shunts by three-dimensional venography using multidetector-row computed tomography during angiography.

PURPOSE: The hepatic vein (HV) can be removed during hepatectomy if there is an effective intrahepatic veno-venous shunt (vv-shunt). We evaluated the efficacy of vv-shunt detection by three-dimensional (3D) venography reconstructed from multidetector-row computed tomography (MDCT) during angiography. METHODS: 3D venography was reconstructed using computer software in 88 patients with intrahepatic tumors. RESULTS: We found that 12 patients had one shunt [4 right hepatic vein (RHV)-middle hepatic vein (MHV) and 12 RHV- inferior right hepatic vein (IRHV)] and 1 patient had 2 shunts (RHV-MHV and -IRHV), confirming a clinically efficient vv-shunt in 14.8% of the patients. In one patient with an RHV-IRHV shunt, the preserved RHV-IRHV shunt worked well and prevented congestion of the postero-caudal subsegment after central bisegmentectomy with partial resection of the RHV ventral trunk for huge hepatocellular carcinoma (HCC). CONCLUSIONS: Although the vv-shunt detection rate by 3D venography is low, a visualized vv-shunt proved to be efficient. Thus, invasive occlusion venography is avoidable if a vv-shunt is seen on 3D venography.

Successful intrahepatic cholangiocarcinoma conversion surgery after administration of fibroblast growth factor receptor inhibitor.

We describe a case of a 47-year-old male patient with initially unresectable intrahepatic cholangiocarcinoma of the right liver lobe with tumor thrombi extending from the right bile duct to the common and left bile ducts. Conventional chemotherapy with gemcitabine and cisplatin for 19 months resulted in progressive disease. Subsequently, a comprehensive genome profile revealed fibroblast growth factor receptor 2 rearrangement, and hence, pemigatinib administration was initiated. After 6 months of pemigatinib therapy, significant shrinking of the tumor and disappearance of the tumor thrombi in the common and left bile duct were observed. Subsequently, the patient underwent conversion surgery, resulting in successful radical resection of the tumor. The patient has been disease-free for 7 months.

Lysophosphatidylcholine acyltransferase 1 altered phospholipid composition and regulated hepatoma progression.

BACKGROUND & AIMS: Several lipid synthesis pathways play important roles in the development and progression of hepatocellular carcinoma (HCC), although the precise molecular mechanisms remain to be elucidated. Here, we show the relationship between HCC progression and alteration of phospholipid composition regulated by lysophosphatidylcholine acyltransferase (LPCAT). METHODS: Molecular lipidomic screening was performed by imaging mass spectrometry (IMS) in 37 resected HCC specimens. RT-PCR and Western blotting were carried out to examine the mRNA and protein levels of LPCATs, which catalyze the conversion of lysophosphatidylcholine (LPC) into phosphatidylcholine (PC) and have substrate specificity for some kinds of fatty acids. We examined the effect of LPCAT1 overexpression or knockdown on cell proliferation, migration, and invasion in HCC cell lines. RESULTS: IMS revealed the increase of PC species with palmitoleic acid or oleic acid at the sn-2-position and the reduction of LPC with palmitic acid at the sn-1-position in HCC tissues. mRNA and protein of LPCAT1, responsible for LPC to PC conversion, were more abundant in HCCs than in the surrounding parenchyma. In cell line experiments, LPCAT1 overexpression enriched PCs observed in IMS and promoted cell proliferation, migration, and invasion. LPCAT1 knockdown did viceversa. CONCLUSIONS: Enrichment or depletion of some specific PCs, was found in HCC by IMS. Alteration of phospholipid composition in HCC would affect tumor character. LPCAT1 modulates phospholipid composition to create favorable conditions to HCC cells. LPCAT1 is a potent target molecule to inhibit HCC progression.

Usefulness of three-dimensional angiographic analysis of perigastric vessels before laparoscopic gastrectomy.

BACKGROUND: Recognition of perigastric vessel anatomy is important to safely perform gastric surgery, especially in the case of laparoscopic gastrectomy. This study was designed to reevaluate the efficacy of preoperative three-dimensional (3D) angiography reconstructed from enhanced multidetector-row computed tomography (MDCT) data and to classify right gastric artery (RGA) branching patterns. METHODS: Perigastric vessel anatomy was preoperatively analyzed using MDCT-based 3D angiography reconstructed by computer software in patients undergoing laparotomic (n = 75) and laparoscopic (n = 25) gastrectomy. Results were compared with intraoperative findings in all cases, and were also compared with maximum intensity projection (MIP) imaging, which is similar to conventional angiography, in 10 patients. RESULTS: Preoperative diagnoses by 3D angiography were identical to intraoperative findings. The rates of branching patterns of the celiac artery and left gastric vein were comparable with previous reports. The detection rate of the right gastric artery (RGA) was 77.0%. Branching patterns of the hepatic artery were classified into four types: right hepatic artery (RHA) + left hepatic artery (LHA) type, replaced RHA + LHA type, RHA + replaced LHA type, and replaced RHA + replaced LHA type. RGA ramification patterns were classified into three types according to hepatic arterial running patterns: distal (68.8%), proximal (14.3%), and caudal (16.9%). Because of vessel overlapping, RGA ramified points were misdiagnosed under MIP images in two of ten cases (20%). CONCLUSIONS: Preoperative 3D angiography is useful for a new system of classifying RGA ramification patterns into three types. With this system, surgeons can perform laparoscopic gastrectomy with lymph node dissection more safely.