Autoimmune cerebellar ataxia is a disease entity that affects the cerebellum and is induced by autoimmune mechanisms. The disease is classified into several etiologies, including gluten ataxia, anti-glutamate decarboxylase (GAD) ataxia, paraneoplastic cerebellar degeneration, primary autoimmune cerebellar ataxia and postinfectious cerebellar ataxia. The autoimmune response in the periphery cross-reacts with similar antigens in the cerebellum due to molecular mimicry. Breakdown of the blood‒brain barrier (BBB) could potentially explain the vulnerability of the cerebellum during the development of autoimmune cerebellar ataxia, as it gives rise to the entry of pathogenic autoantibodies or lymphocytes into the cerebellum. In this review, the maintenance of the BBB under normal conditions and the molecular basis of BBB disruption under pathological conditions are highlighted. Next, the pathomechanism of BBB breakdown in each subtype of autoimmune cerebellar ataxia is discussed. We recently identified glucose-regulated protein (GRP) 78 antibodies in paraneoplastic cerebellar degeneration and Lambert-Eaton myasthenic syndrome, and GRP78 antibodies induced by cross-reactivity with tumors can disrupt the BBB and penetrate anti-P/Q type voltage-gated calcium channel (VGCC) antibodies into the cerebellum, thus leading to cerebellar ataxia in this disease.

A female patient in her 50s who underwent chemotherapy for left primary breast cancer presented with cancerous pleurisy and disseminated intravascular coagulation. Esophagogastroduodenoscopy and liver biopsy revealed gastric and liver cancer. Distinguishing between primary and metastatic cancer by pathological findings is difficult using hematoxylin and eosin staining. We diagnosed and treated simultaneous primary breast cancer (ER-positive) and gastric cancer with liver metastasis (ER-negative), based on differences in estrogen receptor expression. The patient lived for 10 months with chemotherapy. After death, an autopsy was performed because the endoscopic results were atypical for primary gastric cancer, and additional immunohistochemical studies indicated gastric metastasis of breast cancer.

We experienced two cases of renal primary synovial sarcoma. Case 1: A 29-year-old man underwent laparoscopic radical nephrectomy and was originally diagnosed with renal cell carcinoma. Case 2: A 25-year-old man was treated by open radical nephrectomy since radiographical findings indicated tumor invasion to the ureter causing hydronephrosis. Both cases were pathologically diagnosed as renal synovial sarcomas, and were followed using computed tomography. Recurrence was observed within a year in both cases.

T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) has a poor prognosis. Nelarabine has recently shown relatively good results in patients with relapsed or refractory T-ALL/LBL, but requires careful monitoring for neurological complications. A 50-year-old man with early recurrence of T-LBL after allogenic peripheral blood stem cell transplantation received nelarabine monotherapy and achieved complete remission after 1 cycle. He then received umbilical cord blood transplantation, and experienced sustained disturbance of consciousness. He later died of multiple organ failure, and autopsy suggested that nelarabine-induced leukoencephalopathy had caused the disturbance of consciousness. This case suggests that physicians should carefully monitor patients for neurological complications and consider imaging follow-up and consultation with a neurologist.

A 24-year-old man was found to have an ileocecal ulcer by colonoscopy. A pathological diagnosis of diffuse large B-cell lymphoma (DLBCL) with diffuse positive reaction of Epstein-Barr encoding region (EBER) by in situ hybridization was made based on analysis of the specimen. Acquired immunodeficiency syndrome (AIDS) complicated by pneumocystis jirovecii pneumonia was also diagnosed. As no other significant lymphomatous lesions were identified by further examination, a clinical diagnosis of EBV-positive mucocutaneous ulcer (EBVMCU) was made. Rather than performing systemic chemotherapy, the lesion was closely monitored and antiretroviral therapy (ART) for AIDS was started with the hope of treating the lesion through immune reconstitution. The lesion had completely disappeared by day 79 after starting ART, and has not recurred for over 3 years. EBVMCU is known to develop secondary to various immunosuppressive states including AIDS. Here we report a rare case of EBVMCU detected at diagnosis of AIDS that entered complete remission after immune reconstitution by ART.

Laparoscopic proximal gastrectomy(LPG)for upper gastric cancer is still inadequate. We verified the validity of LPG by comparing the surgical outcomes of 15 cases who underwent LPG(PG group)and 14 cases who underwent laparoscopic total gastrectomy(TG group)in 29 cases who underwent laparoscopic surgery for upper gastric cancer at our hospital between January 2014 and December 2022. As a patient background, the PG group was significantly older(p=0.03)than the TG group and tended to have more high-risk cases(p=0.12). As a tumor factor, cancer progression tended to be earlier in the PG group(p=0.05). As a surgical(short-term)outcomes, although the range of lymph nodes dissection was narrow (p<0.01)and the amount of blood loss was significantly lower(p=0.01)in the PG group, there was no difference in operation time or postoperative complications between the 2 groups. Furthermore, there was no difference in the rate of weight loss, the rate of change in nutritional indicators in the medium-term(1 year after surgery), or the long-term prognosis.

A 51-year-old male presented with swelling on the left side of his neck. A diagnosis of thoracic esophageal cancer(Lt type 5a, squamous cell carcinoma, T3N4[16LN]M1[skin, bone, retroperitoneum, lung], cStage Ⅳb)was made, and treatment with a combination of 5-FU plus CDDP and pembrolizumab was initiated. After the 1st round of chemotherapy, there was an increase in metastases in the left cervical lymph node and skin, along with the development of back pain because of an L3 lumbar spine metastasis. Palliative radiotherapy(Σ24 Gy/6 Fr)was administered for all lesions. Subsequently, pembrolizumab was administered for the persistent decline in white blood cell and neutrophil counts. After 6 courses of pembrolizumab, computed tomography(CT)revealed an absence of lesions. Positron emission tomography/CT demonstrated no significant accumulation, prompting a diagnosis of complete response(CR). The patient is currently under pembrolizumab therapy and continues to remain in a state of CR.

As medical insurance coverage for robotic surgery has been expanded in the field of gastrointestinal surgery in Japan, the number of cases undergoing robotic surgery for hepato-biliary-pancreatic disease has been increasing. Therefore, cases with malignant tumors and metastatic lesions tend to undergo robotic operation for both primary tumors and metastases. Herein, we report a case of neuroendocrine tumor(NET)in the pancreatic tail with simultaneous single liver metastasis, which was treated with two-stage robotic-assisted surgery. A 67-year-old female underwent a computed tomography scan and a hypovascularized tumor in the pancreatic tail region and liver was found. A biopsy of the pancreatic tumor by endoscopic ultrasound-guided fine needle aspiration demonstrated a NET G1-2. The liver lesion was diagnosed as a metastatic tumor, considering the other examinations. The patient underwent a robotic distal pancreatectomy(RDP)and was histopathologically diagnosed as NET G2. Sixty-three days after the RDP, a two-stage partial liver resection for the metastatic tumor was performed under robotic assistance. Curative resection was achieved through two-stage robot-assisted surgery, there were no postoperative complications.

In August 2022, a 59-year-old female noted a mass in her umbilicus and sought evaluation at Toyokawa City Hospital. Abdominal computed tomography(CT)scan revealed a 1.6 cm mass in the umbilical region, ascites in the pelvis, and increased absorption in the omentum. Peritoneal dissemination of the carcinoma and Sister Mary Joseph's nodule due to an unknown primary tumor were suspected because no abnormalities were detected during upper and lower gastrointestinal endoscopy. She underwent an umbilical lumpectomy and diagnostic laparoscopy to establish a definitive diagnosis. The surgical findings included numerous white nodules throughout the abdominal cavity. The umbilical mass and omental white nodules were resected. A final diagnosis of epithelial peritoneal mesothelioma was made based on the histopathologic examination. In general, peritoneal mesothelioma has a poor prognosis, and early treatment is essential; however, making a timely definitive diagnosis is difficult. Peritoneal mesothelioma should be included in the differential diagnosis for a patient with unexplained ascites and abdominal pain. Diagnostic laparoscopy and biopsy will facilitate the establishment of a definitive diagnosis.

A 52-year-old male patient with Stage Ⅲc ascending colon cancer underwent laparoscopic right hemicolectomy with D3 lymph node dissection. Adjuvant chemotherapy was administered for 6 months, and no recurrence was observed during the follow-up period. Left lung metastasis was detected and surgically removed 7 years after the initial surgery. He underwent open partial small bowel resection with lymph node dissection when mesenteric lymph node metastasis was identified 2 years later. Although chemotherapy was conducted on the identification of mediastinal lymph node metastasis 2 years later, the mediastinal lymph nodes increased. Although attempted, lymph node dissection was impossible because of the strong adhesion to the trachea. Subsequently, chemotherapy and radiation therapy were administered. However, an infiltration of the mediastinal lymph nodes into the trachea was observed. The patient underwent bronchoscopic laser tumor ablation. The patient died 4 months after the resumption of chemotherapy(18 years after the initial surgery). Mediastinal lymph node recurrence after curative resection for colon cancer is a rare clinical condition. Nevertheless, long-term survival could be achieved by multimodal treatments in such patients.

Monomorphic epitheliotropic intestinal T-cell lymphoma(MEITL)is very rare and aggressive subtype of lymphoma with poor prognosis. A 60-year-old man complaining of abdominal pain was underwent partial resection of the jejunum for panperitonitis with a small intestinal perforation. The histopathological and immunohistochemical findings led to the diagnosis of MEITL. Postoperative course was uneventful. One month after the operation, the patient was scheduled for 6 courses of CHOP regimens. He presented with bowel obstruction twice during the 3 courses of CHOP. As the recurrence of MEITL could not be ruled out, diagnostic laparoscopy was performed. Laparoscopic findings revealed no recurrence and adhesive small bowel obstruction. The patient was followed closely without treatment after 6 courses of CHOP. The patient has been alive without recurrence 18 months after the resection. We reported a case of monomorphic epithelial intestinal T- cell lymphoma causing jejunal perforation.

The patient was a 33-year-old female. She was referred to our hospital from a previous clinic with abdominal pain and vomiting. Contrast-enhanced abdominal CT revealed intussusception, leading to a diagnosis of intussusception with a small intestinal tumor as an advanced part. Intestinal obstruction symptoms were observed, and emergency surgery was performed on the same day. As a technique, single port surgery was selected, and laparoscopic reduction was attempted. However, it was ineffective. The site of intussusception was induced outside the body through a small laparotomy wound, and reduction was performed using Hutchinson's procedure. As an adjacent lymph node was markedly swollen, the mesentery involving this lymph node was dissected in a fan shape, and the tumor was extirpated. The tumor measured 40 mm in long diameter, being a hemicircular, protruding lesion. Histologically, disarray of short spindle tumor cells was observed. Immunostaining showed Kit- and DOG1-negtive reactions and partially α-SMA and desmin-positive reactions, suggesting leiomyosarcoma. With the establishment of an immunostaining-test-based classification, leiomyosarcoma is currently rare. In this study, we report a patient in whom single port surgery for intussusception related to small intestinal leiomyosarcoma was successful.

A 70-year-old male patient was diagnosed with advanced gastric cancer with para-aortic lymph node metastasis. After diagnostic laparoscopy, the patient received 2 courses of neoadjuvant chemotherapy. Subsequently, distal gastrectomy, D2 plus para-aortic lymph node dissection, and Roux-en-Y reconstruction were performed. An enlarged lymph node(No. 16b2)was identified during surgery. The histopathological diagnosis revealed ypT4b, ypN3b, cM1(LYM; No. 16), Stage ⅣB. Chemotherapy with ramucirumab plus nab-paclitaxel was administered at 6 weeks postoperatively. However, after 2 courses of chemotherapy, the patient developed an abscess discharge from the wound, which was confirmed by an abdominal CT scan and diagnosed as an intra-abdominal abscess derived from duodenal perforation. The abscess was drained percutaneously. Subsequently, chemotherapy with nab-paclitaxel, nivolumab, and trifluridine/tipiracil hydrochloride was administered. After the appearance of brain metastases, the treatment was shifted to palliative care. The patient died 2 years and 7 months later from the primary disease.

A 73-year-old, male patient presented with the chief complaint of epigastric pain and received the diagnosis of extensive cholangiocarcinoma after a close examination. Extensive extension of the malignancy into the right and left hepatic ducts precluded a curative resection, and the patient received GC therapy. After 11 courses of GC over about 1 year, no new lesions or tumor progression was observed, and a bile duct mapping biopsy was performed to investigate the possibility of resection conversion. The results showed a marked decrease in atypia, and reactive atypia was diagnosed. A pancreaticoduodenectomy was performed, and histopathologically negative margins were obtained. The response to treatment was Grade Ⅱa according to the Evans classification. At 23 months after the start of treatment and 12 months after surgery, the patient is recurrence-free without adjuvant chemotherapy. Although the evidence for conversion surgery for biliary tract cancer has not been established, the long-term outcomes may be favorable.

During the postoperative follow-up for adrenal tumor for a 78-year-old male patient, a contrast-enhanced computed tomography scan revealed wall thickness with contrast effect in the cystic duct, enlarged lymph nodes along the ileocecal artery, and nodal shadow in the lower lobe of the left lung. First, the collected bile juice at ERC was submitted to cytology multiple times however, no malignant findings were noted. Next, a staging laparoscopy was performed; but the pathological findings of the enlarged lymph nodes and the abdominal lavage cytology showed no malignancy. A nodule in the lower lobe of the left lung was resected for diagnostic and therapeutic purposes, and the pathological diagnosis was primary adenocarcinoma of the lung. Finally the patient underwent exploratory laparotomy for diagnostic purposes. An intraoperative ultrasound- guided needle biopsy for mass lesion located in the medial section of the left liver was performed, and malignant lymphoma was suspected by the intraoperative pathological diagnosis. Cholecystectomy was performed to confirm the histological type, leading to the diagnosis of diffuse large B cell lymphoma. After surgery, the patient underwent 6 courses of rituximab plus CHOP therapy, and the bile duct stricture was improved.

A female patient in her 50s was diagnosed with triple negative breast cancer in the left breast with a buttock metastasis. After neoadjuvant chemotherapy, the patient underwent surgery on the left breast. As the histopathological findings indicated a residual tumor, she was further treated with capecitabine postoperatively. Twenty months postoperatively, a CT scan revealed a tumor on her left buttock. She was also diagnosed with a relapse of the breast cancer after a core needle biopsy. She was treated with atezolizumab and nab-paclitaxel as first-line therapy for the metastasis and with eriburlin as second- line therapy. As she became uncomfortable sitting owing to the regrowth of the buttock tumor, the left buttock tumor was resected. She has been treated with bevacizumab and paclitaxel for subsequent lung metastases.

Phyllodes tumors are uncommon breast neoplasms that constitute 1-2% of breast malignancies. Invasive ductal carcinoma in the epithelial component of phyllodes tumor is very rare. When carcinoma is detected within the specimen, the management of treatment changes completely. We report a rare case of invasive ductal carcinoma arising in a giant borderline malignancy phyllodes tumor in a 51-year-old female patient. A painful 20 cm mass was found in her right breast, and a needle biopsy revealed fibroadenoma or benign phyllodes tumor, and a total mastectomy was performed. Pathological results showed that a borderline malignant phyllodes tumor coexisted with invasive ductal carcinoma. We explained that axillary surgery was necessary because invasive cancer was diagnosed after surgery, but the patient requested follow-up using images. Endocrine therapy was performed as postoperative adjuvant therapy, and the follow-up is underway without recurrence.

A 77-year-old female patient presented with a medical history of 4 cancerous lesions, each with a surgical history. She was referred to our hospital due to anemia. Upon examination, she was diagnosed with transverse colon cancer. Duodenal invasion was suspected, which made performing R0 surgery difficult; therefore, the NAC approach was chosen. Three courses of CAPOX were administered, resulting in tumor obstruction, leading to the formation of an ileum stoma. MSI testing revealed MSI-H, and pembrolizumab treatment was initiated. CT scans showed tumor shrinkage, and PET scans indicated no accumulation, resulting in a cCR. Colon resection including the lesion suspected of stenosis was performed with a strong desire for stoma closure and the determination of potential curative resection. Additionally, a partial resection of the duodenum was performed. Pathological examination did not reveal any evident tumor cells, leading to the determination for a pCR. The patient has been under postoperative surveillance for 1 year without any recurrence.

An 88-year-old woman had been diagnosed with hilar cholangiocarcinoma for 3 years since she received metallic stents for malignant biliary obstruction, and observed without any aggressive medical treatment. She was admitted to our hospital for further investigation of her abdominal pain. Abdominal CT showed an enlarged gallbladder, fluid collection in the right paracolic gutter, and swollen appendix. Laboratory tests showed high-grade inflammation. She was diagnosed with acute perforated appendicitis with acute cholecystitis. Laparoscopic cholecystectomy and appendectomy were performed. Perforation was confirmed intraoperatively in the appendix wall and accumulation of pus was found in the right paracolic gutter. There were no macroscopic findings of metastasis and peritoneal dissemination. Microscopic examination of the resected appendix showed adenocarcinoma cells positive for CK7 and negative for CK20 and CDX2, and were predominantly infiltrated from the muscular layer to the serosa of the appendix wall, with a diagnosis of appendiceal metastasis from hilar cholangiocarcinoma. Metastatic appendiceal carcinoma is rare, and appendiceal metastasis from hilar cholangiocarcinoma is extremely rare. Herein, we report a rare case of metastatic appendiceal carcinoma from hilar bile duct cancer with acute perforated appendicitis and cholecystitis along with findings of previous literature.

There is a liver damage in a serious side effect of regorafenib. Case 1 was a 54-year-old woman, and she had an operation of rectal cancer and metastasized to multiple organs afterwards and started regorafenib as third-line. Erythema exudativum multiform developed on the 8th day after a start and regorafenib was canceled once and reduced on the 21st day when a skin symptom was relieved and restarted. However, because a significant rise of AST, ALT, T -Bil was recognized afterwards, regorafenib was canceled on the 27th day and enforced steroid pulse therapy and was relieved afterwards. Case 2 was a 61-year-old woman, and she had an operation of ascending colon cancer, ovarian metastasis and peritoneum dissemination. Regorafenib was started by frequent occurrence lung metastasis, cancerous pleurisy afterwards as fifth-line. Dissemination erythema developed on the 16th day and a liver damage developed on the 22nd day. Because a rise of AST, ALT went and was prolonged, liver biopsy was enforced in a cause close inspection purpose on the 45th day. A medicamentosus liver damage was diagnosed. The liver enzyme decreased afterwards. It may be easy to make the liver damage by regorafenib serious, and attention is necessary.