Patients with gastric cancer, necessitating surgery, have decreased due to the reduced age-standardized incidence rates and expanded indications for endoscopic resection. The increased rate of early-onset gastric cancer in the West suggested that gastric cancer has become less rare. The effectiveness of radical gastrectomy as a treatment option for gastric cancer has almost plateaued. Further improvement in the long-term outcome will likely be influenced by the emergence of new drugs and the appropriate timing of their administration. The radical gastrectomy technique has become less complex because the survival benefit of various procedures, that had been integrated as components of D2 dissection, were denied by various randomized trials that looked at survival benefit. In modern surgery, a complete resection without postoperative complications is achieved via a minimally invasive approach. In addition, robotic surgery increases the sustainability of surgery in countries like Japan, which suffer from an insufficient number of surgeons. Meanwhile, postgastrectomy symptoms, measured by QOL scales, remain problematic despite decades of research, exploring the various types of reconstruction.

A 65-year-old woman presented to our department with the diagnosis of duodenal papilla cancer in March 2021, and underwent subtotal stomach-preserving pancreatoduodenectomy. On the 4th day after the operation, sudden disturbance of consciousness and visual impairment appeared, and the blood pressure was as abnormally high as 220/140mmHg. There were no other neurological abnormalities, but the visual impairment was light sense. There were no special notes for blood tests. Cerebrospinal fluid examination was also negative for encephalitis and meningitis. There were no special notes for head CT findings. Diffusion-weighted images of head MRI showed hyperintensity in the occipital lobe and parietal lobe, and ADC map and T2 FLAIR images also showed hyperintensity in the same area. Based on clinical symptoms and MRI findings, we diagnosed his illness as posterior reversible encephalopathy syndrome (PRES), and performed antihypertensive control and pain control. On the next day, the disturbance of consciousness improved, and the visual impairment was a manual valve. The hyperintensity area on MRI disappeared on the 28th day after the operation, and the visual impairment was also improved. PRES causes reversible changes in the white matter, especially in the occipital lobe. It is rarely experienced as a postoperative complication and needs to be added to the differential diagnosis of impaired consciousness.

A 78-year-old man presented with a 3-cm right breast tumor, located below the nipple. On physical examination, multiple café au lait spots and thumb's head-sized soft brown masses were observed on the trunk. He was diagnosed with neurofibromatosis type 1 (NF1). Mammary gland ultrasound revealed a 2.9 × 1.6 × 2.3 cm mass. He was diagnosed with invasive ductal breast cancer by needle biopsy. The patient underwent right pectoralis muscle preservation mastectomy + sentinel lymph node biopsy with axillary lymph node dissection. Pathological examination revealed a pT2N1M0 pStage IIB tumor. He was managed postoperatively with oral tamoxifen 20 mg/day. No recurrence was observed. Although NF1 is often associated with malignant tumors, reports of male breast cancer associated with NF1 are rare. We report this case along with a literature review.

A 66-year-old man presented with an abnormal X-ray finding on a medical checkup. A chest CT scan revealed a clearly demarcated nodule in the left lower lobe of the lung (S6). Benign nodule was suspected, and we decided to follow up his clinical course. As the nodule tended to enlarge gradually, we performed surgery for the purpose of diagnosis and treatment. The histopathological diagnosis was amelanotic malignant melanoma. No lesions which could be the primary were detected in other organs including the skin. Accordingly, we diagnosed his illness as primary malignant melanoma of the lung. Two years and three months had elapsed since the surgery without any apparent findings suggestive of recurrence.

Primary malignant melanoma of the lung is believed to be extremely rare. The prognosis is poor, and many patients die within one year after surgery. This case was of amelanotic, and the tumor enlarged gradually, that were different clinical features from those of ordinary lung melanomas.

A 52-year-old man presented to our department for further examination of anemia. Upper gastrointestinal endoscopy showed multiple early gastric cancer lesions in the antrum. Endoscopic submucosal dissection was performed, and on histological examination, the lesions were positive for Epstein-Barr virus (EBV)-encoded RNA (EBER), leading to a diagnosis of EBV-associated gastric cancer. One lesion had a depth of SM2 and extensive venous invasion ; therefore, additional surgical resection was performed. Laparoscopic total gastrectomy showed new EBV-positive early gastric lesions in the surgically resected specimen, resulting in a total of eight lesions. In addition to the cancerous lesions, a collection of EBER-positive atypical gland ducts suggestive of precancerous lesions was observed. A surgical case of EBV-associated, multiple, early gastric cancers, is reported along with a literature review. When treating cases with multiple gastric cancers, it is important to consider the possibility of EBV-related gastric cancer and determine treatment strategies based on patient background and potential simultaneous or metachronous carcinogenesis.

After resuscitation from a cardiopulmonary arrest, a 63-year-old man underwent percutaneous coronary intervention and was admitted to the intensive care unit. On the 14th day of hospitalization, he was weaned from the ventilator and resumed eating. Abdominal distention and pain appeared, and the patient was diagnosed with intestinal obstruction. His symptoms did not improve after placement of an ileus tube. A partial resection of the small intestine was performed on the 22nd day of hospitalization. Based on the cytomegalovirus (CMV) antigenemia assay and histopathological examination, CMV enteritis was diagnosed, and ganciclovir was initiated. The patient had diarrhea, persisting since the postoperative period, which rapidly improved and he was discharged from the hospital on day 40 of hospitalization. Although there is no clear treatment policy or prophylaxis for CMV infection in patients without immunosuppressive backgrounds, it is important to be aware of the possibility of CMV enteritis causing intestinal obstruction and requiring surgical intervention following a cardiopulmonary arrest.

We report a rare case of strangulated ileus caused by knotting of the ileum in Meckel's diverticulum. A 41-year-old man with no history of surgery visited our hospital due to sudden severe abdominal pain and vomiting. Abdominal contrast-enhanced computed tomography showed a dilated small intestine with a closed-loop sign and ascites in the Douglas pouch. We considered it to be a strangulated ileus and performed an emergency operation. Intraoperative findings showed that the ileum was strangulated due to a knot in a long blind pouch and caused intestinal necrosis. We untied the knot and resected the blind pouch with the necrotic intestine, and end-to-end anastomosis was performed. Macroscopic findings showed that the resected specimen of the blind pouch (9.5 cm) was located approximately 50 cm from the end of the ileum on the opposite side of the mesenteric attachment site. Histopathological examination revealed that the blind pouch was Meckel's diverticulum. We finally diagnosed strangulation of the ileum due to knot formation in Meckel's diverticulum.

A 29-year-old woman was diagnosed with descending colon intussusception caused by descending colon cancer ; therefore, we performed an urgent laparoscopic left hemicolectomy with D3 dissection. Adhesive intestinal obstruction developed early in the postoperative period, and we performed another laparoscopic surgery on postoperative day 12. On the 13th day after the reoperation, an abdominal enhanced computed tomography revealed superior mesenteric artery syndrome. Conservative treatments such as decompression and enteral nutrition with a double elementary diet (W-ED) tube were initiated ; however, no symptomatic remission was achieved, and we performed laparoscopic duodenal jejunostomy on the 62nd day after the reoperation. The postoperative course was uneventful and the patient was discharged on the 9th day after the last operation. We report a case of intussusception caused by young-onset descending colon cancer followed by postoperative superior mesenteric artery syndrome treated by laparoscopic surgery, along with a review of the literature.

The patient was a 55-year-old man with a history of appendicitis that resolved with conservative treatment. One year later, he visited the urology department with a complaint of gross hematuria and was referred to our department. Cystoscopy showed a fistula at the outer side of the right ureteral opening, and abdominal magnetic resonance imaging showed a cystic lesion in the bladder wall, with the ileum in contact with the bladder. Based on the above, an appendico-vesical fistula due to appendicitis or a malignant tumor of the appendix was diagnosed, and laparoscopic ileo-cecal resection (D3 dissection) with partial cystectomy jointly with the urology department was performed. Since the urology department was scheduled to perform a partial cystectomy through a small laparotomy, the oral and anal intestinal tracts were separated in the abdominal cavity, a small laparotomy wound was made in the midline of the lower abdomen, the bladder wall was resected in the area of adhesion, and the specimen was removed from the small laparotomy wound. Pathological examination showed no malignant findings. An appendico-vesical fistula is a rare form of intestinal vesical fistula, and it is very difficult to determine whether it is benign or malignant preoperatively. This is the third case of an appendico-vesical fistula treated by laparoscope assisted surgery in Japan, and it is reported with a review of the literature.

Case 1. A 40-year-old man, who underwent conservative therapy for complicated appendicitis 3 months earlier, was found to have persistent swelling of the appendix without inflammation on computed tomography (CT) before interval appendectomy. A type 2 tumor was found in the cecum obstructing the appendiceal orifice on colonoscopy. Radical ileocecal resection with lymph node dissection was performed for advanced carcinoma of the cecum. Case 2. A 42-year-old man was found to have persistent swelling of the appendix and enlarged lymph nodes along the ileocolic artery on CT three months after conservative treatment for complicated appendicitis. Colonoscopy showed an ulcerative lesion around the appendiceal orifice with the pathological diagnosis of adenocarcinoma of the appendix. Radical ileocecal resection with the small intestine was performed. In conclusion, the possibility of hidden malignancy of the cecum and appendix should be considered in cases of persistent morphological changes of the appendix without inflammatory changes at the follow-up imaging study before interval appendectomy, especially in patients over the age of 40 years.

A 53-year-old male patient underwent robot-assisted high anterior resection for rectal cancer with double stapling anastomosis using a 25-mm circular stapler. He was diagnosed postoperatively with pT3N1aM0 pStageIIIb rectal cancer, so he received adjuvant chemotherapy with XELOX. At the 6-month postoperative visit, leakage of mucous feces was observed, and CT showed a cystic lesion with a 34-mm long diameter at the anastomosis with no internal nodule. Lower gastrointestinal endoscopy revealed an elevated submucosal tumor-like lesion at the anastomosis. MRI showed a dumbbell-shaped cystic lesion with a well-defined, homogeneous mass with T1 low signal and T2 high signal with no internal nodule. From these results, the diagnosis of implantation cyst was made, and the patient was followed up for observation. Two years and six months have passed since the surgery without any increase in the size of the implantation cyst or recurrence of rectal cancer.

The case of a patient who required dialysis after developing severe electrolyte abnormalities and renal insufficiency associated with a villous tumor of the rectum is reported.

A 70-year-old woman had noticed bloody stool and diarrhea two years earlier, but she had not sought medical advice. She presented at a local clinic because the diarrhea symptoms had worsened, and since a mass was palpable on rectal examination, she was referred to our hospital with suspected rectal cancer. Because she also had no appetite, she was immediately admitted on the same day, and she was started on dialysis one week later when blood tests indicated acute renal failure. Lower gastrointestinal endoscopy showed a circumferential villous tumor in the rectum, which was diagnosed as adenocarcinoma in adenoma on the basis of the biopsy results. On contrast-enhanced computed tomography, a large amount of fluid was seen to have accumulated in the rectum, and an elevated lesion with a maximum diameter of approximately 10 cm was protruding into the rectal cavity. It was considered that mucus secretion from this villous tumor of the rectum had caused electrolyte depletion syndrome, and that this had triggered acute renal failure. After the patient's general condition had improved with hemodialysis, Hartmann's procedure was performed. The acute renal failure started to improve immediately after the operation so that the patient no longer required dialysis, and her subsequent course was uneventful.

A 70-year-old man was referred to our hospital with a diagnosis of ruptured hepatocellular carcinoma in segment 4 of the liver and transcatheter arterial embolization (TAE) was subsequently carried out on an emergency basis. At that time a contrast-enhanced CT scan revealed a portal vein thrombus (Vp4) from the left branch to the main trunk. Systemic chemotherapy was selected, and we started treatment with lenvatinib (12mg/day) in December 2019. The tumor responded well to the 6-week treatment, CT showed shrinkage of both the tumor and portal vein thrombus, and conversion surgery was decided. Laparoscopic left hepatectomy was performed in February 2020. Intraoperatively, the left portal vein was divided after the absence of tumor thrombus was confirmed with intraoperative ultrasonography. The postoperative course was uneventful and the patient has been alive for 2 years postoperatively without recurrence.

A 76-year-old man presenting with abdominal pain and vomiting consulted the previous hospital, and an abdominal ultrasonography revealed an enlarged gallbladder. He was referred to our hospital, and was diagnosed as acute cholecystitis by an abdominal CT scan. After conservative treatment, he was scheduled to undergo cholecystectomy. Although, he had no cholecystitis symptoms, preoperative abdominal CT scan revealed aggravated cholecystitis, and MRI demonstrated a fistula between the gallbladder and transverse colon. After additional fasting and antibiotic treatment, we performed surgery for cholecystocolonic fistula. At surgery the fistula was confirmed, and open subtotal cholecystectomy and partial transverse colon resection was carried out. There were no postoperative complications, and he was discharged on 15^th postoperative day. The histological diagnosis of the resected specimens was xanthogranulomatous cholecystitis (XGC). We report this very rare case of XGC associated with cholecystocolonic fistula.

The case of a patient with gallbladder cancer-like xanthogranulomatous cholecystitis after long-term placement of an endoscopic transpapillary gallbladder drainage (ETGBD) tube is reported. A 68-year-old man presented to our hospital with a complaint of abdominal pain. With the diagnosis of acute cholecystitis, ETGBD was performed, and thereafter, he did not visit our hospital. Eight months after ETGBD placement, he went to another hospital with the complaint of epigastric pain. Gastric cancer was incidentally discovered, and he was referred to our hospital. Computed tomography showed a 6-mm-thick gallbladder wall, and gallbladder cancer was suspected. An open total gastrectomy with whole-layer cholecystectomy was performed. The pathological diagnosis of the gallbladder was xanthogranulomatous cholecystitis.

Patients may not return to the hospital after ETGBD as their symptoms of acute cholecystitis abate. Long-term placement of an ETGBD tube may cause chronic inflammation of the gallbladder. It is important to educate patients that an ETGBD tube should be removed when the acute inflammation recedes, and cholecystectomy is recommended.

The patient was a 66-year-old man who underwent gastrectomy with Billroth II reconstruction for duodenal ulcer perforation 29 years earlier and had a history of conservative treatment for afferent loop syndrome. Computed tomography (CT) showed dilation of the afferent loop and an increased concentration of peripancreatic fat. The patient was admitted to the hospital with a diagnosis of acute pancreatitis due to afferent loop syndrome. A nasogastric tube was placed in the afferent loop under endoscopy for decompression. Despite sufficient decompression of the afferent loop, severe acute pancreatitis progressed, and CT on the 10th day of admission showed extensive abscess formation from the lower mediastinum to the caudal space of the left kidney. At the stage of encapsulation, open necrosectomy and Braun anastomosis were performed on the 29th day of admission. After the operation, the inflammatory complication (minor leakage) subsided with drain management, and the patient was discharged on the 77th day of admission. Although the afferent loop syndrome rarely causes acute pancreatitis, the mortality rate is high when the pancreatitis becomes severe. It is important to keep in mind that there is a possibility that afferent loop syndrome leads to severe acute pancreatitis even after decompression of the afferent loop.

The patient was a 74-year-old man, who had been followed up since 2015 for intraductal papillary mucinous neoplasm (IPMN) in the pancreatic tail at the Department of Gastroenterology in our hospital. In 2020, he presented with fever and anorexia, and was diagnosed with perforation to omental bursa of IPMN in an abdominal enhanced CT scan. In the operation, mucus accumulation into omental bursa from the ruptured cyst in the pancreas tail was observed. There were no obvious liver metastases and lymphadenopathy. Rapid cytology with abdominal lavage was also negative. Distal pancreatosplenectomy was performed. The patient was discharged on the 14th postoperative day. The pathological diagnosis was well-differentiated mucus-producing adenocarcinoma arising in the IPMN, and the patient was treated with adjuvant chemotherapy with S-1 for 6 months, which was started in the second postoperative month. At 1 year postoperatively, the patient is alive without recurrence.

In this case, there is a concern about recurrence with peritoneal pseudomyxoma. However, no effective way has been reported to prevent IPMC-induced peritoneal pseudomyxoma. Therefore, we administered adjuvant chemotherapy for 6 months, according to the treatment for pancreatic cancer. Careful follow-up should be continued.

An 89-year-old woman presented to our hospital with a chief complaint of gastric discomfort for the past 2 or 3 months. She had a history of laparoscopic abdominoperineal resection and laparoscopic transverse colostomy. Computed tomography showed a dilated intestinal canal and collecting vessels on the ventral side of the lesser curvature, and emergency surgery was performed after gastric tube decompression based on the diagnosis of an internal hernia. There was an abnormal, 5-cm-long hiatus at the lesser curvature, and the small intestine was fitted from the dorsal side of the hiatus to the ventral side. No intestinal necrosis was observed, and the abnormal hiatus was sutured closed. The patient had a good postoperative course and was discharged home on the seventh postoperative day, and no recurrence has been observed eight months after the surgery. In this case, the small intestine passed through the open omental bursa due to partial loss of the mesentery of the transverse colon caused by a previous operation, and it was thought to have entered into the hiatus that was caused by some unknown mechanism. Although a lesser omental hernia is one of the rarest internal hernias, its characteristic imaging findings may lead to a preoperative diagnosis.

Background : Internal hernias through the greater and lesser omentum are extremely rare ; however, delayed diagnosis sometimes leads to small bowel necrosis. The objective of this clinical case report was to describe the case of a patient with greater and lesser transomental sac hernia, where provide early diagnosis and immediate surgery proved effective.

Case presentation : A 35-year-old female with no history of abdominal surgery was admitted to our hospital with a complaint of persistent upper abdominal pain. Radiography and abdominal computed tomography (CT) revealed dilated loops of the small intestine ; she was diagnosed with acute gastroenteritis and referred to our hospital. Despite fasting and hydration, the patient's pain persisted. On the third day of hospitalization, abdominal enhanced CT showed increased ascites and a section of the small intestine fitted into the lesser omentum. The patient was diagnosed with strangulated internal hernia. Emergency surgery was performed one day after decompression with an ileus tube. Intraoperative examination revealed that approximately 10 cm of the ileum had penetrated the greater and lesser omentum. Intestinal resection was not performed because the ileum was not necrotic. The postoperative course was uneventful.

Discussion and Conclusion : Greater and lesser transomental sac hernias are extremely rare, but require early diagnosis and surgery.

This study presents the case of a 45-year-old man diagnosed with a 40-mm retroperitoneal tumor between the left common iliac artery and lumbar spine by computed tomography. Intraoperatively, the tumor adhered to the left common iliac artery and vein. Since a malignancy was not excluded, these blood vessels were partially resected and reconstructed. On pathological examination, the tumor was composed of oval- and spindle-shaped eosinophilic cells. Furthermore, immunostaining revealed that the tumor was positive for the melanocytic (HMB-45 and Melan-A) and smooth muscle markers (α-SMA), and negative for the epithelial marker. The final pathological diagnosis was a perivascular epithelioid cell tumor (PEComa), a rare mesenchymal tumor, composed of perivascular epithelioid cells, that develop in various organs. PEComas mainly occur in the uterus, but they rarely occur in the retroperitoneal space. This study documented a rare case of PEComa. Further case reports are needed to get deep understanding of this tumor.