Relapse of Ulcerative Colitis with Immune Thrombocytopenia and Pyoderma Gangrenosum Subsequent to Receiving COVID-19 Vaccination.

This case illustrates the complex interactions of the immune responses after vaccination and highlights their potential connections to various autoimmune conditions. A 22-year-old man with quiescent ulcerative colitis (UC) presented with abdominal pain, rectal bleeding, and thrombocytopenia 7 days after receiving the third coronavirus disease 2019 mRNA vaccination. Laboratory data confirmed the diagnosis of immune thrombocytopenia. High-dose intravenous immunoglobulin administration boosted the patient's platelet count. Simultaneously, colonoscopy revealed that his UC had relapsed. Although salazosulfapyridine briefly improved his symptoms, his stool frequency worsened one week later. The patient also developed pyoderma gangrenosum. Subsequent treatment with infliximab notably improved both pyoderma gangrenosum and UC.

Percutaneous endoscopic necrosectomy for walled-off necrosis in the retroperitoneal space of the elderly: A case report.

BACKGROUND: Walled-off necrosis (WON) is a late complication of acute pancreatitis possibly with a fatal outcome. Even for WON spreading to the retroperitoneal space, percutaneous endoscopic necrosectomy (PEN) can be an alternate approach to surgical necrosectomy, particularly for the older individuals or patients with poor condition because of WON. CASE SUMMARY: An 88-year-old man was admitted to our hospital with a jaundice. Endoscopic retrograde cholangiopancreatography (ERCP) was performed to improve jaundice; however, post-ERCP pancreatitis developed. The inflammation of pancreatitis spread widely from the right retroperitoneal cavity to the pelvis, and WON was formed 4 wk later. A percutaneous drainage tube was placed into the WON under computed tomography guidance. However, the drainage did not ameliorate clinical symptoms including fever, which assured less invasive necrosectomy. A metallic stent for the upper gastrointestinal (GI) tract was placed from the percutaneous drainage route. An upper GI endoscope was inserted into the inside of the WON through the metallic stent, and the necrotic tissues were bluntly removed with a snare forceps. Ten times of these necrosectomies resulted in the near-complete removal of necrotic tissues. These procedures consequently abated his fever and remarkable improvement in blood tests. CONCLUSION: PEN for WON occurring in the retroperitoneal space was safe and effective for very old individuals.

Guide Wire Selection (Straight vs. Angled) in Endoscopic Retrograde Cholangiopancreatography Using a Normal Contrast Catheter Performed by a Trainee: A Single-Center Prospective Randomized Controlled Cross-Over Study.

INTRODUCTION: Wire-guided cannulation (WGC) during endoscopic retrograde cholangiopancreatography (ERCP) is a selective biliary cannulation technique aimed at improving the successful selective biliary cannulation rate and reducing the rate of post-ERCP pancreatitis (PEP) incidence. This study aimed to evaluate the effectiveness of angled-tip guidewires (AGW) vs. straight-tip guidewires (SGW) for biliary cannulation via WGC by a trainee. METHODS: We conducted a prospective, single-center, open-labeled, randomized, and controlled trial. Fifty-seven patients were enrolled in this study and assigned randomly to two groups (Group A to S and Group S to A). In this study, we started selective biliary cannulation via WGC with an AGW or an SGW for 7 min. If cannulation was unsuccessful, the other guidewire was used, and cannulation was continued for another 7 min (cross-over method). RESULTS: The selective biliary cannulation success rate over 14 min was significantly higher with an AGW compared with an SGW over 14 min (57.8% vs. 34.3%, p = 0.04) and for the second 7-min segment (36.4% vs. 0%, p = 0.04). No significant difference was found for adverse events such as pancreatitis between the two guidewires. CONCLUSIONS: Our results suggest that an AGW is recommended for WGC performed by a trainee.

Clinical benefit of subsequent chemotherapy after drug-induced interstitial lung disease in pancreatic cancer patients: a multicenter retrospective study from Japan.

PURPOSE: Drug-induced interstitial lung disease (ILD) is not a rare adverse event in the current chemotherapy strategy for pancreatic ductal adenocarcinoma (PDAC). Thus, we aimed to find the optimal management for PDAC patients with a history of ILD induced by a gemcitabine-based regimen. METHODS: We conducted a multicenter retrospective study. The primary endpoint was the overall survival (OS) of patients who underwent either S-1 monotherapy or FOLFOX after the onset of ILD. Toxicity data was also analyzed in the 2 groups. RESULTS: Twenty-four patients were diagnosed with ILD and 17 patients who received subsequent chemotherapy were enrolled in the study. Among 17 patients who were managed with subsequent chemotherapy after recovering from ILD, we did not observe significant difference in OS between S-1 and FOLFOX (290.0 days vs. undefined, p = 0.39). Relapse of drug-induced ILD was not observed in all cases during the course. Overall, severe adverse events (CTCAE Grade 3 or 4) were observed in 3 patients (23.1%) in S-1 treatment group and 1 patient (25.0%) in FOLFOX treatment group (p = 0.93). CONCLUSIONS: S-1 monotherapy and FOLFOX are comparable as the subsequent chemotherapy after gemcitabine-based chemotherapy-induced ILD in unresectable PDAC.

A multicenter comparative study of endoscopic ultrasound-guided fine-needle biopsy using a Franseen needle versus conventional endoscopic ultrasound-guided fine-needle aspiration to evaluate microsatellite instability in patients with unresectable pancreatic cancer.

BACKGROUND/AIMS: Immune checkpoint blockade has recently been reported to be effective in treating microsatellite instability (MSI)-high tumors. Therefore, sufficient sampling of histological specimens is necessary in cases of unresectable pancreatic cancer (UR-PC). This multicenter study investigated the efficacy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using a Franseen needle for MSI evaluation in patients with UR-PC. METHODS: A total of 89 patients with UR-PC who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) or EUS-FNB using 22-G needles at three hospitals in Japan (2018-2021) were enrolled. Fifty-six of these patients (FNB 23 and FNA 33) were followed up or evaluated for MSI. Patient characteristics, UR-PC data, and procedural outcomes were compared between patients who underwent EUS-FNB and those who underwent EUS-FNA. RESULTS: No significant difference in terms of sufficient tissue acquisition for histology was observed between patients who underwent EUS-FNB and those who underwent EUS-FNA. MSI evaluation was possible significantly more with tissue samples obtained using EUS-FNB than with tissue samples obtained using EUS-FNA (82.6% [19/23] vs. 45.5% [15/33], respectively; p<0.01). In the multivariate analysis, EUS-FNB was the only significant factor influencing the possibility of MSI evaluation. CONCLUSION: EUS-FNB using a Franseen needle is desirable for ensuring sufficient tissue acquisition for MSI evaluation.

Clinical Differences in c-Myc Expression in Early-Stage Gastric Neoplasia: A Retrospective Study Based on the WHO Classification.

c-Myc is an oncogene that is dysregulated in various cancers. Early gastric neoplasia with c-Myc expression has been reported as a more malignant lesion. This study clarifies the differences in c-Myc expression in early gastric neoplasia based on the WHO classification. Samples from 100 patients with differentiated-type early gastric neoplasia, who underwent endoscopic submucosal dissection between March 2020 and January 2021, were stained for c-Myc. One hundred lesions were classified as low-grade dysplasia, high-grade dysplasia, or intramucosal adenocarcinoma. The staining intensity and extent were scored. A hierarchical cluster analysis for a clinicopathological analysis among the groups, the chi-square test, Bonferroni correction, and residual analysis were performed. Subgroup one and two consisted of 39 patients; while subgroup three consisted of 22. Significant differences among various characteristics were observed between these subgroups. The frequency of low-grade dysplasia was significantly higher, while that of high-grade dysplasia was significantly lower in subgroup three. The frequency of intramucosal adenocarcinoma was significantly higher in subgroup one. The c-Myc positivity rate was significantly higher in subgroup one compared with that in subgroup three. c-Myc expression distinctly differed in early gastric neoplasia. c-Myc-negative low-grade dysplasia may be separately categorized from c-Myc-positive low-grade dysplasia, high-grade dysplasia, and intramucosal adenocarcinoma.

A Prospective Multicenter Randomized Feasibility Trial of Double-guidewire Techniques for Difficult Biliary Cannulation Comparing a New Double-guidewire-supported Sphincterotome (MagicTome) to a Conventional Device.

Objective To evaluate the effectiveness and safety of the double-guidewire technique (DGT) using a new double-guidewire-supported sphincterotome (MagicTome) for patients who required endoscopic retrograde cholangiopancreatography (ERCP) for biliary cannulation. Methods This prospective multicenter randomized feasibility trial involved patients with difficult biliary cannulation at any of the three study sites from June 2017 to October 2018. Patients were assigned to the DGT with MagicTome (MDGT) initially performed group and the conventional DGT (CDGT) initially performed group. The success rates of biliary cannulation by MDGT and CDGT and the ERCP-related complications were evaluated. Results Twenty-eight patients were included in this study. No significant difference was observed in the success rates of first attempts and crossover attempts between the groups (p=0.69 and p=1.00). Furthermore, no significant difference was observed in the success rate of biliary cannulation between MDGT and CDGT (62.5% and 75.0%, respectively; p=0.48). CDGT was successful in two of four patients with malignant biliary obstruction. MDGT was successful in all four patients with malignant biliary obstruction, including the two for whom CDGT was unsuccessful. Post-ERCP pancreatitis occurred in only one MDGT case. Conclusion MDGT is safe for biliary cannulation and can be used in cases where biliary cannulation by CDGT is difficult.

Risk of Pancreatitis Following Biliary Stenting With/Without Endoscopic Sphincterotomy: A Randomized Controlled Trial.

BACKGROUND & AIMS: The efficacy of endoscopic sphincterotomy (ES) before endoscopic transpapillary biliary drainage in preventing post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) has not been established. The aim of this study was to evaluate the effect of performing ES before biliary stent/tube placement on the occurrence of PEP. METHODS: Three hundred seventy patients with biliary stricture requiring endoscopic biliary stenting were enrolled and randomly allocated to the ES group (n = 185) or non-ES group (n = 185). All participants were followed up for 30 days after the procedure. The data and occurrence of adverse events were prospectively collected. The primary outcome measure of this study was the incidence of PEP within 2 days of initial transpapillary biliary drainage. Secondary outcome measures were the incidence of other adverse events related to biliary stent/tube placement. RESULTS: PEP occurred in 36 patients (20.6%) in the non-ES group and in 7 patients (3.9%) in the ES group (P < .001). The difference in the incidence of PEP between the 2 groups in the per-protocol population was 16.7% (95% confidence interval, 10.1%-23.3%), which was not within the noninferiority margin of 6%. Except for bleeding, the incidences of other adverse events were not significantly different between the groups. CONCLUSION: ES before endoscopic biliary stenting could have the preventive effect on the occurrence of PEP in patients with biliary stricture. University Hospital Medical Information Network Number, UMIN000025727.University Hospital Medical Information Network Clinical Trial Registry URL: https://www.umin.ac.jp/ctr/index.htm.

Pilot Study of Acupuncture's Antispasmodic Effect on Upper Gastrointestinal Tract during Endoscopic Submucosal Dissection for Early Gastric Cancer: Controlled Clinical Trial.

A prospective study was conducted in patients with early-stage gastric cancer to determine the efficacy and safety of acupuncture stimulation as an antispasmodic compared with conventional medication during the procedure of endoscopic submucosal dissection (ESD) of the upper gastrointestinal tract. This study was a prospective single blinded quasi-randomized controlled trial. Seventy-three patients who were scheduled to undergo ESD for gastric cancer at Aizu Medical Center between 19 February 2016 and 30 June 2016 were assessed for eligibility for the study. Sixty out of 73 patients were included in the study and assigned into two intervention groups: medication group (MG) and acupuncture group (AG). Ease of the procedure was evaluated using modified NIWA classification (MNC) by endoscopist considering the frequency and amplitude of the upper gastrointestinal peristalsis. For the statistical analysis, Mann-Whitney test was used to compare the differences of MNC values (baseline and end of procedure) between two groups. The difference of MNC found in the AG (-2.00 (-3.0 to -2.0)) was significantly greater than that in the MG (-1.00 (-2.0 to -1.0), p < 0.0001, Mann-Whitney test). We consider that acupuncture to the abdomen could be an alternative antispasmodic method during upper gastrointestinal endoscopic procedure.

Validity of Endoscopic Ultrasound Findings of Chronic Pancreatitis: Evaluation from the Viewpoint of Disease Risk Factors.

BACKGROUND: The diagnosis of chronic pancreatitis (CP) using endoscopic ultrasound (EUS) criteria, referred to as the Rosemont classification (RC), has been widely performed. However, the validity of the RC, which was based on expert opinion, is still controversial. If EUS findings are associated with CP, then they should be associated with risk factors for CP. In this study, to verify the appropriateness of the RC and each EUS finding, we performed a retrospective analysis from the viewpoint of risk factors for CP. SUMMARY: Three hundred and forty-four patients were enrolled in this study. Clinical background characteristics that associate with CP were alcohol intake, smoking, history of acute pancreatitis (AP), and age. The correlation between EUS criteria for CP and clinical background was investigated. All EUS findings except the presence of cysts showed significant correlations with one or 2 of the 3 following factors: ethanol (EtOH) intake, smoking status, and history of AP. Results of the univariate and multivariate analyses showed that 3 factors (EtOH intake, smoking, and history of AP) other than age were positively correlated with the RC. Moreover, the risk of progression from normal to consistent CP to indeterminate and suggestive CP was found to increase with increasing EtOH intake. Key Messages: The RC and each EUS finding was validated from the viewpoint of risk factors for CP.

Adverse events of endoscopic ultrasound-guided fine-needle aspiration for histologic diagnosis in Japanese tertiary centers: Multicenter retrospective study.

BACKGROUND AND AIMS: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is used for the histopathological diagnosis of any type of gastrointestinal disease. Few adverse events are experienced with this procedure; however, the actual rate of adverse events remains unclear. This study aimed to clarify the current status of cases that experienced adverse events related to the EUS-FNA procedure used for histopathologic diagnoses. METHODS: A retrospective analysis of cases with EUS-FNA-related adverse events in Japanese tertiary centers was conducted by assessing the following clinical data: basic case information, FNA technique, type of procedural adverse events, and prognosis. RESULTS: Of the 13,566 EUS-FNA cases overall, the total number of cases in which adverse events related to EUS-FNA occurred was 234. The incidence of EUS-FNA-related adverse events was ~1.7%. Bleeding and pancreatitis cases accounted for ~49.1% and 26.5% of all adverse events, respectively. Bleeding was the most common adverse event with only seven cases requiring blood transfusion. In cases with neuroendocrine tumors, pancreatitis was the most frequent adverse event. Needle tract seeding because of EUS-FNA was observed during the follow-up period in only ~0.1% of cases with pancreatic cancer. There was no mortality because of adverse events caused by EUS-FNA. CONCLUSIONS: This study revealed that the adverse events-related EUS-FNA for histopathologic diagnoses were not severe conditions, and had low incidence.

Diagnostic performance of artificial intelligence to identify deeply invasive colorectal cancer on non-magnified plain endoscopic images.

Background and study aims Colorectal cancers (CRC) with deep submucosal invasion (T1b) could be metastatic lesions. However, endoscopic images of T1b CRC resemble those of mucosal CRCs (Tis) or with superficial invasion (T1a). The aim of this study was to develop an automatic computer-aided diagnosis (CAD) system to identify T1b CRC based on plain endoscopic images. Patients and methods In two hospitals, 1839 non-magnified plain endoscopic images from 313 CRCs (Tis 134, T1a 46, T1b 56, beyond T1b 37) with sessile morphology were extracted for training. A CAD system was trained with the data augmented by rotation, saturation, resizing and exposure adjustment. Diagnostic performance was assessed using another dataset including 44 CRCs (Tis 23, T1b 21) from a third hospital. CAD generated a probability level for T1b diagnosis for each image, and > 95 % of probability level was defined as T1b. Lesions with at least one image with a probability level > 0.95 were regarded as T1b. Primary outcome is specificity. Six physicians separately read the same testing dataset. Results Specificity was 87 % (95 % confidence interval: 66-97) for CAD, 100 % (85-100) for Expert 1, 96 % (78-100) for Expert 2, 61 % (39-80) for both gastroenterology trainees, 48 % (27-69) for Novice 1 and 22 % (7-44) for Novice 2. Significant differences were observed between CAD and both novices ( P  = 0.013, P  = 0.0003). Other diagnostic values of CAD were slightly lower than of the two experts. Conclusions Specificity of CAD was superior to novices and possibly to gastroenterology trainees but slightly inferior to experts.

Duodenal Stenosis Due to Carcinoma of the Lower Bile Duct: A Case Report.

An 83-year-old man was referred to our hospital for a detailed evaluation for vomiting. Esophagogastroduodenoscopy and abdominal computed tomography showed duodenal stenosis with wall thickness. Biopsy including endoscopic ultrasound-guided fine-needle aspiration of the thickened wall showed inflammation without malignancy. During the clinical course, wall thickening of the distal bile duct appeared. Biopsy under endoscopic retrograde cholangiography showed papillary adenocarcinoma. Surgery revealed that the tumor had widely invaded the duodenal wall from the outside; therefore, only gastrojejunostomy was performed. It was hypothesized that the cholangiocarcinoma had progressed to the serosal side, disseminated in the peritoneum, infiltrated the duodenal serosa, and caused duodenal stenosis.

Endoscopic ultrasound-guided coil deployment with sclerotherapy for isolated gastric varices: Case series of feasibility, safety, and long-term follow-up.

The purpose of the present study is to report our experience of endoscopic ultrasound-guided coil deployment with sclerotherapy (EUS-CS) for isolated gastric varices (IGV) through a case series. Eight consecutive patients who had risky IGV were prospectively enrolled. EUS-CS was performed according to the following procedures: (i) several coils were first deployed in the IGV under EUS guidance; (ii) contrast medium was subsequently injected without removing the needle; (iii) if the infused contrast medium stayed in the IGV and feeding vein, sclerosant was then injected to obliterate the IGV and feeders. Coil deployment in the IGV was successfully performed in all cases. Sclerosant was injected both into the IGV and feeders in seven patients (87.5%). There was no adverse event during the procedure. During a median follow-up of 57 months, one patient who could not inject the sclerosant into IGV and feeders had an early hemorrhagic recurrence. Our case series showed that EUS-CS could be a feasible and safe procedure for the treatment of IGV.

The Feasibility and Histological Diagnostic Accuracy of Novel Menghini Needle (EUS Sonopsy CY™) for Endoscopic Ultrasound-Guided Fine-Needle Aspiration Biopsy of Solid Pancreatic Masses: A Prospective Crossover Study Comparing Standard Biopsy Needles.

BACKGROUND AND OBJECTIVES: Recently, a 21G Menghini-type needle for EUS-guided fine-needle aspiration biopsy (EUS-FNAB) has been developed. The stylet of the EUS Sonopsy CY™ remains inside the needle during aspiration. Therefore, it is expected to obtain higher-quality histological core specimens without crushing the material or blood contamination. The aim of this study is to evaluate the feasibility and diagnostic accuracy of EUS-FNAB of solid pancreatic masses with this new biopsy needle. METHODS: A total of 30 patients with solid pancreatic masses who underwent EUS-FNAB with two different types of needles, EUS Sonopsy™ and ProCore™, were included in a prospective, randomized, controlled, crossover study. All the pancreatic masses were punctured with the two needles and were randomized regarding the order of the needle to be used. The primary outcome was to compare the diagnostic accuracy and the rates of tissue acquisition of the two needles. RESULTS: The tissue acquisition rate was not significantly different between the EUS Sonopsy CY™ needle and the ProCore™ needle (78.6% vs. 82.1%, P = 1.00). The histological diagnostic accuracy was also similar between the two needles (73% vs. 80%, P = .63). There was also no difference regarding the accuracy of cytology alone and the combination of both histological and cytological assessments between the EUS Sonopsy CY™ needle and the ProCore™ needle (90% vs. 87%, P = 1.00 and 90% vs. 90%, P = 1.00, respectively). CONCLUSIONS: EUS Sonopsy CY™ is a reliable device for EUS-FNAB of solid pancreatic masses.

New endoscopic ultrasonography criteria for malignant lymphadenopathy based on inter-rater agreement.

BACKGROUND AND AIMS: Various studies have been previously conducted on the diagnosis of lymphadenopathy as benign or malignant, but the results vary. These studies did not describe the inter-rater agreement on the EUS features of lymphadenopathy. In this study, we evaluate the inter-rater agreement on EUS features and propose EUS diagnostic norms for lymphadenopathy based on inter-rater agreement. METHOD: A total of 68 lymph nodes subjected to EUS-fine needle aspiration (FNA) were reviewed by five endoscopic experts. The EUS features evaluated lymph node size, shape, border, margin, echogenicity, homogeneity, and the hilum of the lymph node. Inter-rater agreement (multi-rater kappa statics) was performed. We established new criteria using results with a high degree of inter-rater agreement from EUS features and compared them with the former criteria. RESULT: There was a moderate agreement on shape, kappa (K) = 0.44 (95% confidence interval [CI]: 0.34-0.54), and fair agreement on echogenicity, homogeneity, border, and hilum of the lymph node, K (95% CI) = 0.33 (0.17-0.38), 0.34 (0.26-0.35), 0.22 (0.21-0.31), and 0.22 (0.11-0.26), respectively. This resulted in the establishment of new EUS diagnostic criteria using shape, long axis > 20 mm and short axis > 10 mm. New criteria were superior to old criteria (area under the curve 0.82 vs 0.52, P < 0.001). CONCLUSION: EUS diagnostic criteria for lymphadenopathy based on inter-rater agreement were more accurate than old criteria. This result will be useful for the diagnosis of lymphadenopathy.

Endoscopic Mucosal Resection Performed Underwater for Nonampullary Duodenal Epithelial Tumor: Evaluation of Feasibility and Safety.

OBJECTIVES: Recently, opportunities to encounter superficial nonampullary duodenal epithelial tumor (SNADET) have increased. EMR and ESD are performed to treat SNADET. However, the rate of perforation is higher than that of other gastrointestinal lesions, regardless of which method is used. Underwater EMR (UW-EMR) is immersion treatment of SNADET, which has low risk of perforation and can remove lesions safely and completely. In the present study, we retrospectively investigated patients in whom UW-EMR was performed to evaluate the feasibility and safety of UW-EMR for the treatment of SNADET. METHODS: The primary endpoint was to evaluate the feasibility of UW-EMR for the treatment of SNADET, and secondary objective was to determine the operation's safety. RESULTS: There were 14 participants, with a total of 16 lesions, who underwent UW-EMR between August 2015 and December 2017. Histological heteromorphism revealed that seven patients had low-grade adenoma, seven had high-grade adenoma, and two had adenocarcinoma. En bloc resection was performed in 14 lesions. In two patients, nodular lesions were observed in the scar and biopsy confirmed recurrences. There were no serious adverse events including bleeding or perforation. CONCLUSIONS: UW-EMR may be a safe and effective treatment method for SNADET, if its therapeutic indication is adequately considered.

A Case of Obstructive Jaundice Caused by Metastasis of Ovarian Cancer to the Duodenal Major Papilla.

Ovarian cancer often occurs distant metastasis to the peritoneum, liver, lungs, and lymph nodes. However, there has been no reported case of direct metastasis to the duodenal major papilla. We herein reported 72-year-old woman with history of ovarian cancer surgery 11 years ago presenting with obstructive jaundice. Abdominal CT showed a small mass in the distal bile duct. Forceps biopsy from the small mass was done under endoscopic retrograde cholangiography, and histologic examination revealed adenocarcinoma. Pancreaticoduodenectomy was performed and diagnosed immunohistochemically direct metastasis to the papilla from ovarian cancer. The duodenal major papilla is known to be rich in lymph vessels, and these lymph vessels are considered the likely pathway of metastasis in this case.

Simultaneous Gastric Metastasis From Renal Cell Carcinoma: A Case Report and Literature Review.

While some reports are available regarding metachronous gastric metastasis from renal cell carcinoma after treatment, there are few reports of primary lesion detection based on the diagnosis of a gastric metastatic lesion. The patient in this case was an 80-year-old woman who underwent upper gastrointestinal endoscopy after having developed anorexia 2 months earlier. A submucosal tumor with central umbilication was found in the gastric greater curvature. Endoscopic ultrasonography revealed a solid and hypoechoic mass with hypervascularity on color Doppler imaging that proliferated mainly within the submucosal layer. There was partial exposure of the tumor on the superficial layer. Biopsy was performed, as a neuroendocrine tumor was suspected; however, histopathological findings with immunostaining revealed gastric metastasis from clear renal cell carcinoma. Subsequently, contrast enhanced computed tomography showed right renal cell carcinoma and liver metastasis. Thus, molecularly targeted drug treatment was initiated by the Department of Urology. Our findings indicate that a primary lesion can be identified and prognosis can be assumed based on biopsy of the gastric metastatic lesion. Immunostaining of biopsy samples collected endoscopically could help achieve definite diagnosis.