A case report of perihilar cholangiocarcinoma in a patient with situs inversus totalis.

Situs inversus totalis is a rare congenital malformation in which organs are positioned in a mirror-image relationship to normal conditions. It often presents with vascular and biliary malformations. Only a few reports have pointed out the surgical difficulties in patients with situs inversus totalis, especially in those with perihilar cholangiocarcinoma. This report describes a 66-year-old male patient who underwent left hemihepatectomy (S5, 6, 7, and 8) with combined resection of the caudate lobe (S1), extrahepatic bile duct, and regional lymph nodes for perihilar cholangiocarcinoma with situs inversus totalis. Cholangiocarcinoma was mainly located in the perihilar area and progressed extensively into the bile duct. Surgery was performed after careful evaluation of the unusual anatomy. Although several vascular anomalies required delicate manipulation, the procedures were performed without major intraoperative complications. Postoperatively, bile leakage occurred, but the patient recovered with drainage treatment. The patient was discharged on the 29th postoperative day. Adjuvant chemotherapy with S-1 was administered for approximately 6 months. There was no recurrence 15 months postoperatively. Appropriate imaging studies and an understanding of unusual anatomy make surgery safe and provide suitable treatment for patients with situs inversus totalis.

Skeletal muscle mass and function are affected by pancreatic atrophy, pancreatic exocrine insufficiency and poor nutritional status in patients with chronic pancreatitis.

BACKGROUND/OBJECTIVE: Previous studies have demonstrated that sarcopenia is frequently observed in patients with chronic pancreatitis (CP). However, most studies have defined sarcopenia solely based on skeletal muscle (SM) loss, and muscle weakness such as grip strength (GS) reduction has not been considered. We aimed to clarify whether SM loss and reduced GS have different associations with clinical characteristics and pancreatic imaging findings in patients with CP. METHODS: One hundred two patients with CP were enrolled. We defined SM loss by the SM index at the third lumbar vertebra on CT (<42 cm2/m2 for males and <38 cm2/m2 for females), and reduced GS by < 28 kg for males and <18 kg for females. RESULTS: Fifty-seven (55.9 %) patients had SM loss, 21 (20.6 %) had reduced GS, and 17 (16.7 %) had both. Patients with SM loss had lower body mass index, weaker GS, higher Controlling Nutritional Status score, lower serum lipase level, and lower urinary para-aminobenzoic acid excretion rate, suggesting worse nutritional status and pancreatic exocrine insufficiency. On CT, main pancreatic duct dilatation and parenchymal atrophy were more frequent in patients with SM loss than in those without it. Patients with reduced GS were older and had worse nutritional status than those without it. CONCLUSIONS: SM loss was associated with pancreatic exocrine insufficiency, low nutritional status, and pancreatic imaging findings such as parenchymal atrophy and main pancreatic duct dilatation, whereas older age and low nutritional status led to additional reduced GS.

A Novel Dry Simulator Model for Learning Comprehensive Endoscopic Retrograde Cholangiopancreatography/Endoscopic Sphincterotomy Procedures while Minimizing Adverse Bleeding Events (with Video).

INTRODUCTION: Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy (EST) are essential skills for performing endoscopic cholangiopancreatic procedures. However, these procedures have a high incidence of adverse events, and current training predominantly relies on patient-based approaches. Herein, we aimed to develop an ERCP/EST simulator model to address the need for safer training alternatives, especially for learners with limited ERCP experience. METHODS: The model was designed to facilitate the use of actual endoscopic devices, supporting learning objectives that align with the components of the validated Bethesda ERCP Skill Assessment Tool (BESAT). BESAT focuses on skills, such as papillary alignment, maintenance of duodenoscope position, gentle and efficient cannulation, controlled sphincterotomy in the correct trajectory, and guidewire manipulation. Thirty gastroenterology trainees used the simulator between May 2022 and March 2023, and their satisfaction was assessed using a visual analog scale (VAS) and pre- and post-training questionnaires. RESULTS: The novel simulator model comprised a disposable duodenal papillary section, suitable for incision with an electrosurgical knife, alongside washable upper gastrointestinal tract and bile duct sections for repeated use. The duodenal papillary section enabled reproduction of a realistic endoscope position and the adverse bleeding events due to improper incisions. The bile duct section allowed for the reproduction of fluoroscopic-like images, enabling learners to practice guidewire guidance and insertion of other devices. Following training, the median VAS score reflecting the expectation for model learning significantly increased from 69.5 (interquartile range [IQR]: 55.5-76.5) to 85.5 (IQR: 78.0-92.0) (p < 0.01). All participants expressed a desire for repeated simulator training sessions. CONCLUSIONS: This innovative simulator could serve as a practical educational tool, particularly beneficial for novices in ERCP. It could facilitate hands-on practice with actual devices, enhancing procedural fluency and understanding of precise incisions to minimize the risk of bleeding complications during EST.

A case of synchronous double cancers consisting of maxillary gingival carcinoma and intraductal papillary mucinous carcinoma, invasive: case report.

BACKGROUND: The development of synchronous multiple primary cancers is one of the major causes of death in patients with head and neck cancer. Herein, we report a case of synchronous intraductal papillary mucinous carcinoma (IPMC), invasive in a patient with maxillary gingival carcinoma. CASE PRESENTATION: A 73-year-old female visited our hospital complaining of a mass on the left side of the maxillary gingiva. Intraorally, an exophytic tumor, 50 × 25 mm in size, was found on the gingiva of the left maxillary posterior, and a diagnosis of squamous cell carcinoma was revealed by cytology. Emission tomography/ computed tomography with 18 Fluorodeoxyglucose-Positron (18FDG- PET/ CT) showed increased accumulation in the left maxillary gingiva, the left side of cervical lymph nodes, and the main pancreatic duct. The pancreatic ductal tumor was performed the biopsy at esophagogastroduodenoscopy (EGD) and resulted in a pathological diagnosis of IPMC, invasive. The patient was diagnosed as synchronous double primary cancers consisting of maxillary gingival carcinoma cT4aN2bM0 and IPMC, invasive cT3N0M0. She refused radical treatment, and died 11 months later. CONCLUSION: 18FDG- PET/ CT, EGD and multidisciplinary approach is required for the detection and determining the treatment strategy of synchronous double primary cancers.

GATA6 and CK5 Stratify the Survival of Patients With Pancreatic Cancer Undergoing Neoadjuvant Chemotherapy.

Relevant protein expression of GATA6, CK5, vimentin, and mucins using immunohistochemistry was assessed for predicting the prognosis of and chemotherapy efficacy in patients with pancreatic cancers (PCs). The protein expression was examined in 159 PCs resected after neoadjuvant chemotherapy (NAC-PCs) and compared with that of 120 matched biopsy specimens taken before NAC. KRAS mutations were assessed by digital PCR. NAC-PCs were classified by GATA6 expression initially and CK5 expression subsequently into 4 types: classical-type (n = 22) with GATA6-high (≥50%)/CK5-low (<10%) PCs; hybrid-type (n = 45) with GATA6-high/CK5-high (≥10%) PCs; basal-like-type (n = 53) with GATA6-low (<50%)/CK5-high (≥30%) PCs; and null-type (n = 39) with GATA6-low/CK5-low (<30%) PCs, which resulted in clear stratification of patient prognosis. The classical-type was associated with the most favorable prognosis, whereas the null-type was associated with the worst prognosis (multivariate hazard ratio: 3.56; 95% CI, 1.63-7.77; P = .0015). The hybrid and basal-like types correlated with in-between levels of prognosis. The risk of hepatic recurrence was lower in the classical-type than in null (multivariate odds ratio [mOR]: 0.18; 95% CI, 0.04-0.96; P = .0449) and basal-like (mOR: 0.24; 95% CI, 0.05-1.16; P =.0750) types. By contrast, the risk of locoregional recurrence was higher in the classical-type than in the basal-like-type (mOR: 5.03; 95% CI, 1.20-21.1; P = .0272). The hybrid-type was subclassified into transition and coexpression patterns with different gastric mucin expression levels. High levels of vimentin (≥10%, n = 30) in pre-NAC-PC tissues was associated with poor prognosis (P = .0256). Phenotypic transitions between pre-NAC and post-NAC-PCs were common (73/120; 61%). PCs with NAC regression grades 2 and 3 showed a transition to poorer prognostic phenotypes (P = .0497). KRAS mutations were not associated with these phenotypes. In conclusion, GATA6 and CK5 immunohistochemical expression phenotypes may stratify the survival of patients with NAC-PCs and reflect post-NAC phenotypic transitions associated with poor prognosis. Prompt evaluation of immunohistochemical phenotypes may contribute to designing a precision therapeutic strategy for patients with PCs.

The PRSS3P2 and TRY7 deletion copy number variant modifies risk for chronic pancreatitis.

BACKGROUND: PRSS1 and PRSS2 constitute the only functional copies of a tandemly-arranged five-trypsinogen-gene cluster (i.e., PRSS1, PRSS3P1, PRSS3P2, TRY7 and PRSS2) on chromosome 7q35. Variants in PRSS1 and PRSS2, including missense and copy number variants (CNVs), have been reported to predispose to or protect against chronic pancreatitis (CP). We wondered whether a common trypsinogen pseudogene deletion CNV (that removes two of the three trypsinogen pseudogenes, PRSS3P2 and TRY7) might be associated with CP causation/predisposition. METHODS: We analyzed the common PRSS3P2 and TRY7 deletion CNV in a total of 1536 CP patients and 3506 controls from France, Germany, India and Japan by means of quantitative fluorescent multiplex polymerase chain reaction. RESULTS: We demonstrated that the deletion CNV variant was associated with a protective effect against CP in the French, German and Japanese cohorts whilst a trend toward the same association was noted in the Indian cohort. Meta-analysis under a dominant model yielded a pooled odds ratio (OR) of 0.68 (95% confidence interval (CI) 0.52-0.89; p = 0.005) whereas an allele-based meta-analysis yielded a pooled OR of 0.84 (95% CI 0.77-0.92; p = 0.0001). This protective effect is explicable by reference to the recent finding that the still functional PRSS3P2/TRY7 pseudogene enhancers upregulate pancreatic PRSS2 expression. CONCLUSIONS: The common PRSS3P2 and TRY7 deletion CNV was associated with a reduced risk for CP. This finding provides additional support for the emerging view that dysregulated PRSS2 expression represents a discrete mechanism underlying CP predisposition or protection.

The M-ANNHEIM-AiP-Activity-Score is useful for predicting relapse in patients with type 1 autoimmune pancreatitis.

BACKGROUND/OBJECTIVES: Proper assessment of disease activity and prediction of relapse are crucial for the management of autoimmune pancreatitis (AIP). The M-ANNHEIM-AiP-Activity-Score (MAAS) has been proposed to determine disease activity and predict relapse in German and Swedish patients with AIP. MAAS is calculated using six categories: pain report, pain control, exocrine insufficiency, endocrine insufficiency, imaging, and complications. This study aimed to clarify the usefulness of MAAS to predict relapse in Japanese patients with type 1 AIP. METHODS: We retrospectively analyzed 117 patients with type 1 AIP undergoing initial and maintenance steroid treatments at our institute between April 2006 and March 2021. AIP was diagnosed according to the Japanese Diagnostic Criteria for AIP 2018. We examined the association of MAAS with relapse during and after maintenance treatment. RESULTS: MAAS (median, 8 points) at the start of the initial treatment was reduced after treatment (median, 4 points; P < 0.001). A MAAS ≥11 points at the start of the initial treatment was associated with relapse. The initial treatment-induced reduction of MAAS<60% was more frequent in patients with relapse (75.0%) than in patients without relapse (37.6%; P = 0.007). MAAS at the start of maintenance treatment was higher for patients with relapse (median, 5 points) than that for patients without relapse (median, 4 points; P = 0.007). MAAS ≥4 points at the start of maintenance treatment was associated with subsequent relapse. CONCLUSIONS: MAAS is useful for predicting relapse in patients with type 1 AIP undergoing maintenance therapy.

A case of occult pancreaticobiliary reflux due to endoscopically confirmed relaxation of the Oddi sphincter.

An otherwise healthy 45-year-old woman had been experiencing intermittent right upper abdominal pain for the past 1 year. Computed tomography showed pneumobilia and pancreatic duct emphysema despite a normal duodenal papilla. Magnetic resonance cholangiopancreatography and endoscopic ultrasound confirmed bile duct dilation but without a pancreaticobiliary maljunction. Duodenoscopy detected a slightly sunken, unfixed, and spontaneously enlarged duodenal papilla. During the cholangiogram, the Oddi sphincter was relaxed and the catheter could be easily inserted into the bile duct. Further, no findings suggestive of pancreaticobiliary maljunction were observed, and the contrast medium leaked spontaneously from the duodenal papilla. As biliary amylase level was high, we surmised the occurrence of occult pancreaticobiliary reflux due to relaxation of the Oddi sphincter. However, as there are no guidelines on the management of this condition, we did not offer any treatment. Nevertheless, the patient continued to experience similar symptoms and was retested 1 year later with similar results. As occult pancreaticobiliary reflux was reconfirmed, we suggested that the patient undergo laparoscopic extrahepatic bile duct resection and cholecystectomy, which is the standard treatment for pancreaticobiliary maljunction. Pathological evaluation revealed fibrous thickening of the bile duct wall and chronic cholecystitis, which are typical findings of pancreaticobiliary reflux. Even though pancreaticobiliary reflux is mainly observed in pancreaticobiliary maljunction, it has also been reported in normal patients. Here, we describe a novel mechanism of pancreaticobiliary reflux, namely, a relaxed or defective Oddi sphincter.

Favorable response after radiation therapy for intraductal papillary mucinous neoplasms manifesting as acute recurrent pancreatitis: A case report.

BACKGROUND: There has been an increasing number of elderly patients with intraductal papillary mucinous neoplasm (IPMN), who are surgically intolerant and require less invasive treatment options, which are limited. In the present study, we report a case of IPMN presenting with acute recurrent pancreatitis (ARP), in which radiation therapy effectively prevented further attacks of ARP and reduced tumor volume. CASE SUMMARY: An 83-year-old man was referred to our hospital with an asymptomatic incidental pancreatic cyst. Endoscopic ultrasound imaging and magnetic resonance cholangiopancreatography revealed a multiloculated tumor in the head of the pancreas, with dilated pancreatic ducts and mural nodules. The patient was diagnosed with mixed-type IPMN, and five years later, he developed ARP. Several endoscopic pancreatic ductal balloon dilatations failed to prevent further ARP attacks. Surgery was considered clinically inappropriate because of his old age and comorbidities. He was referred to our department for radiation therapy targeted at those lesions causing intraductal hypertension and radiation was administered at a dose of 50 Gy. An magnetic resonance imaging scan taken ten weeks after treatment revealed a decrease in tumor size and improvement of pancreatic duct dilatation. Fourteen months later, he remains symptom-free from ARP. CONCLUSION: This case highlights the important role of radiation therapy in mitigating the signs and symptoms of ARP in patients with inoperable IPMN.

Utility of Endoscopic Ultrasound-Guided Fine-Needle Aspiration and Biopsy for Histological Diagnosis of Type 2 Autoimmune Pancreatitis.

In Japan, type 1 autoimmune pancreatitis (AIP) is the most common type of AIP; type 2 AIP is rare. The aim of this study was to clarify the usefulness of endoscopic ultrasound-guided fine-needle aspiration and biopsy (EUS-FNAB) for the diagnosis of type 2 AIP. We analyzed the tissue specimens of 10 patients with suspected type 2 AIP who underwent EUS-FNAB at our hospital between April 2009 and March 2021 for tissue volume and histopathological diagnostic performance. The male-to-female ratio of the patients was 8:2, and the patient age (mean ± standard deviation) was 35.6 ± 15.5 years. EUS-FNAB provided sufficient tissue volume, with high-power field >10 in eight patients (80.0%). Based on the International Consensus Diagnostic Criteria (ICDC), four patients (40.0%) had histological findings corresponding to ICDC level 1, and five patients (50.0%) had histological findings corresponding to ICDC level 2. The results of this study show that EUS-FNB can be considered an alternative method to resection and core-needle biopsy for the collection of tissue samples of type 2 AIP.

A case of refractory esophageal stricture due to occult gastrinoma of the duodenum.

Gastrinoma may cause refractory esophageal stricture due to gastro-esophageal reflux disease (GERD), but imaging technologies have limited power in its diagnosis. A 74-year-old female with a history of peptic ulcers suffered from repeated epigastralgia, and she visited a local hospital. An esophago-gastro-duodenoscopy (EGD) demonstrated severe reflux esophagitis and multiple peptic ulcers. Blood examination revealed a high value of fasting serum gastrin. Multi-detector computed tomography showed a hypervascular and tiny nodule in duodenal bulb, although other imaging technologies did not. Short-term medication with a proton pump inhibitor or potassium-competitive acid blocker was intermittently provided, but dysphagia was repeatedly worsened, and she was referred to our division. Serum hypergastrinemia was retained, and EGD reexamination depicted esophageal stricture, treated by multiple sessions of endoscopic balloon dilatation. Primary tumor was not identified by the morphological imaging technologies, but a selective arterial secretagogue injection test suggested its existence in the duodenum or pancreatic head. Pancreaticoduodenectomy was performed, and histological study identified 2 mm-sized microgastrinoma buried in Brunner`s glands on the posterior wall of the duodenum bulb. We reported a case with difficulty in diagnosis of the smallest sporadic gastrinoma of the duodenum, which might cause refractory GERD-associated stricture.

Pancreatic mixed acinar-neuroendocrine carcinoma in a patient with a germline BRCA2 mutation: a case report.

Loss of function in the BRCA2 gene exacerbates ovarian, breast, and pancreatic ductal cancer risk. Despite being implicated in the pancreatic ductal epithelium carcinogenesis, the involvement of a germline BRCA2 mutation in acinar and endocrine cells is less reported. A 45-year-old woman with a history of breast cancer was referred to our hospital for a detailed examination of epigastric pain. Her father had pancreatic cancer, and her paternal aunt had a history of breast cancer. Contrast-enhanced computed tomography revealed a round tumor with a contrast effect in the pancreatic head. The patient underwent pancreaticoduodenectomy, and postoperative pathology and genetic testing revealed amphicrine-type mixed acinar-neuroendocrine carcinoma with a germline BRCA2 mutation. Recent studies have reported the BRCA2 mutation in genome sequencing of pancreatic acinar cell carcinoma and neuroendocrine tumor; perhaps, genetic testing for the BRCA2 mutation is feasible for patients with mixed neuroendocrine-non-neuroendocrine neoplasm.

Pancreaticoduodenectomy for pancreatic head cancer with cavernous transformation of the portal vein: a case report.

BACKGROUND: Cavernous transformation of the portal vein (CTPV) due to extrahepatic portal vein obstruction is a rare vascular anomaly. Since its symptoms usually appear in childhood, most of the adult cases are detected unexpectedly with other diseases. Only a few reports have described surgical difficulties in patients with CTPV. We report a case of pancreatic head cancer with CTPV in a patient who underwent pancreaticoduodenectomy. CASE PRESENTATION: A 77-year-old man with epigastric and back pain was referred to our hospital. Computed tomography revealed a tumor in the pancreatic head and a CTPV near the hepatic hilum. CTPV consisted of two main collateral vessels connected by multiple surrounding small vessels. Also, portal vein obstruction was observed near the hepatic hilum, which was far from the pancreatic head tumor. After confirming that there was no distant metastasis by a thorough whole-body search, we performed a pancreaticoduodenectomy following neoadjuvant chemotherapy. During the operation, we carefully manipulated the area of the CTPV and omitted lymph node dissection in the hepatoduodenal ligament to prevent massive venous bleeding and intestinal congestion. Pancreaticoduodenectomy was performed without any intraoperative complications and the postoperative course was uneventful. Complete tumor resection was histologically confirmed. CONCLUSION: Although pancreaticoduodenectomy for patients with CTPV involves many surgical difficulties, we successfully performed it by determining specific treatment strategies tailored to the patient and following careful and delicate surgical procedures.

Clinical features and prognostic impact of asymptomatic pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal, and early diagnosis is challenging. Because patients who present with symptoms generally have advanced-stage diseases, analysis of asymptomatic PDAC provides invaluable information for developing strategies for early diagnosis. Here, we reviewed 577 patients with PDAC (372 diagnosed with symptoms [symptomatic group] and 205 without symptoms [asymptomatic group]) diagnosed at our institute. Among the 205 asymptomatic PDAC patients, 109 were detected during follow-up/work-up for other diseases, 61 because of new-onset or exacerbation of diabetes mellitus, and 35 in a medical check-up. Asymptomatic PDAC is characterized by smaller tumor size, earlier disease stage, and higher resectability than those of symptomatic PDAC. In 22.7% of asymptomatic cases, indirect findings, e.g., dilatation of the main pancreatic duct, triggered PDAC detection. Although pancreatic tumors were less frequently detected, overall abnormality detection rates on imaging studies were nearly 100% in asymptomatic PDAC. Asymptomatic PDAC had a better prognosis (median survival time, 881 days) than symptomatic PDAC (342 days, P < 0.001). In conclusion, diagnosis of PDAC in the asymptomatic stage is associated with early diagnosis and a better prognosis. Incidental detection of abnormal findings during the follow-up/work-up for other diseases provides important opportunities for early diagnosis of asymptomatic PDAC.

A New Preoperative Scoring System for Predicting Aggressiveness of Non-Functioning Pancreatic Neuroendocrine Neoplasms.

The management of non-functioning pancreatic neuroendocrine neoplasms (NF-PanNENs) is still controversial. This study aimed to develop a new scoring system for treatment decisions at initial diagnosis based on the identification of the predictive factors for aggressive NF-PanNENs. Seventy-seven patients who had been pathologically diagnosed with NF-PanNENs were enrolled. We retrospectively reviewed 13 variables that could be assessed preoperatively. Univariate and multivariate stepwise logistic regression analyses were performed to identify factors for the aggressiveness of NF-PanNENs, and a scoring system was developed by assigning weighted points proportional to their ß regression coefficient. Tumor size > 20 mm on contrast-enhanced computed tomography, tumor non-vascularity, and Ki-67 labeling index ≥5% on endoscopic ultrasound-guided fine-needle aspiration specimens were identified as independent factors for predicting the aggressiveness of NF-PanNENs. The new scoring system, developed using the identified factors, had an excellent discrimination ability, with area under the curve of 0.92 (95% CI, 0.85-0.99), and good calibration (p = 0.72, Hosmer-Lemeshow test). Ten-year overall survival rates in low-risk (0 point), intermediate-risk (1 to 2 points), and high-risk (3 to 4 points) groups were 100%, 90.9%, and 24.3%, respectively. This new scoring system would be useful for treatment decisions and prognostic prediction at initial diagnosis.

Focal Parenchymal Atrophy of the Pancreas Is Frequently Observed on Pre-Diagnostic Computed Tomography in Patients with Pancreatic Cancer: A Case-Control Study.

Pancreatic ductal adenocarcinoma (PDAC) accounts for the majority of all pancreatic cancers and is highly lethal. Focal parenchymal atrophy (FPA) of the pancreas has been reported as a characteristic imaging finding of early PDAC. Here, we reviewed 76 patients with PDAC who underwent computed tomography (CT) between 6 months and 3 years before PDAC diagnosis, as well as 76 sex- and age-matched controls without PDAC on CT examinations separated by at least 5 years. FPA was observed corresponding to the location of the subsequent tumor on pre-diagnostic CT in 14/44 (31.8%) patients between 6 months and 1 year, 14/51 (27.5%) patients between 1 and 2 years, and 9/41 (22.0%) patients between 2 and 3 years before PDAC diagnosis. Overall, FPA was more frequently observed in patients with PDAC (26/76; 34.2%) on pre-diagnostic CT than that in controls (3/76; 3.9%) (p < 0.001). FPA was observed before the appearance of cut-off/dilatation of the main pancreatic duct, suggesting that FPA might be the earliest sign of PDAC. FPA was less frequently found in tumors in the pancreatic head (3/27; 11.1%) than in those in the body (14/30; 46.7%) or tail (9/19; 47.4%). FPA may predict the subsequent PDAC diagnosis, serving as an important imaging sign for the early diagnosis of pancreatic cancer.

Acinar Cell Carcinoma with Morphological Change in One Month.

A 64-year-old man was admitted to our hospital to undergo examination of a pancreatic tumor accompanied by sudden epigastric pain. The tumor had a well-defined oval shape that was mostly less enhanced, with the exception of part of the tumor on the pancreatic head side, on contrast enhanced (CE)-CT. However, CE-CT performed one-month later revealed that the viable part of the tumor grew toward the pancreatic tail with the reduction of necrotic tissue. We performed distal pancreatectomy and the tumor was diagnosed as acinar cell carcinoma (ACC). One important characteristic of ACC is that it may develop morphological changes within a short period of time.

IgG4-related Diaphragmatic Inflammatory Pseudotumor.

A 71-year-old man underwent surgery for a pancreatic neuroendocrine tumor. Follow-up imaging showed swelling of the remnant pancreas, and he was histologically diagnosed with autoimmune pancreatitis based on endoscopic ultrasonography-guided fine-needle aspiration specimens. After two years, a tumor appeared on the liver surface. Although we planned to perform laparoscopic partial hepatectomy, the intraoperative findings showed that the tumor was located in the diaphragm. Partial resection of the diaphragm was performed, and the final diagnosis was an immunoglobulin G4-related inflammatory pseudotumor in the diaphragm. To our knowledge, this is the first reported case of an immunoglobulin G4-related diaphragmatic inflammatory pseudotumor.