We report a case of intrapancreatic bile duct solitary recurrence 4 years postoperatively for pT2 gallbladder cancer. A 58-year-old woman underwent laparoscopic cholecystectomy for a growing gallbladder polyp. Her histopathological findings included well-differentiated adenocarcinoma, pT2a, ly0, v0, ne0, pCM0, pEM0, R0. Consequently, gallbladder bed resection, extrahepatic bile duct resection, choledochojejunostomy, and lymph node dissection were performed. Following which, residual cancer was not reported. Postoperatively, abdominal computed tomography(CT)scans were performed at 6-month intervals. A 3-cm mass with poor contrast was observed in the pancreatic head 4 years postoperatively without main pancreatic duct dilation or pancreatic parenchymal atrophy, and the mass was considered as a recurrent nodule of gallbladder cancer. The recurrent mass could no longer be identified after three courses of GEM+CDDP combination therapy. Subsequently, the disease was determined to be curable, and a pancreaticoduodenectomy was performed. Her postoperative course was uneventful, and the patient was discharged after 30 days. A clearly demarcated white nodular mass measuring 5 mm in diameter was observed in the posterior part of the pancreas, which was a poorly differentiated adenocarcinoma. In this case, the tumor was macroscopically and histologically atypical for primary cancer and was considered a gallbladder cancer recurrence with its main site in the bile duct.

A 81-year-old woman was referred to our department for further examination and treatment after upper gastrointestinal endoscopy revealed a type 3 tumor in the antrum. CT scan revealed a primary tumor with extramural invasion in the antrum and large lymph nodes bordering the pancreas, as well as in the right side of cardia. A diagnosis of advanced gastric cancer cT4aN2M0, cStage Ⅲ was made. She was administered chemotherapy with nivolumab and SOX. After 2 courses of treatment, CT scan showed marked reduction of the primary tumor and lymph nodes. Therefore, laparoscopic gastrectomy(D2 dissection+Roux-en-Y reconstruction)was performed. Histopathological findings showed that the primary tumor was confined to the sub serosal tissue and no lymph node metastases were observed. The patient is currently alive without recurrence and treated with S-1 monotherapy. Chemotherapy with nivolumab and SOX is considered to be an effective treatment strategy for advanced gastric cancer with advanced lymph node metastases.

We report a case of IPMC complicated with obstructive pancreatitis due to perforation of the duodenum, in which radical surgery was performed. The patient was a 50-year-old man. He was referred to his previous doctor for a thorough examination of jaundice and liver damage. ERCP showed a tumour exposed in the duodenal bulb and IPMC was suspected, but biopsy showed no malignant findings. The patient was treated for obstructive pancreatitis, but the inflammatory response remained elevated. On imaging evaluation, inflammation around the pancreatic body tail remained, but inflammation around the portal vein was relatively mild. The pancreaticoduodenectomy was performed with sub-total gastric preservation. The pathology results showed a diagnosis of IPMC, with destruction of the duodenal wall due to compressible intraductal tumour growth, and a wide area of acute inflammation. The patient was treated with S-1 as adjuvant post-operative chemotherapy for 6 months and is currently recurrence-free.

A man in his 60s presented with jaundice. He was diagnosed with BR pancreatic head cancer with SMV infiltration. He underwent subtotal stomach-preserving pancreaticoduodenectomy(SSPPD)and SMV resection. He had an uneventful postoperative course and was discharged on day 13. Pathology revealed T4N1(3/28)M0, Stage Ⅳa. After adjuvant chemotherapy, a solitary left lung nodule was detected 2 years and 6 months postoperatively. It was diagnosed as recurrence. After chemotherapy, thoracoscopic partial lung resection was performed 3 years and 6 months postoperatively. Three months later, another solitary nodule was found in the left lung. Thus, a second thoracoscopic partial lung resection was performed 6 years and 1 month postoperatively to remove the lung metastasis. There has been no recurrence since, and the patient has achieved long-term survival of over 9 years after the initial surgery. This is a rare case of long-term survival after 2 metastasis resections, which we report with a brief literature review.

While pancreatic ductal adenocarcinoma (PDAC) originates from exocrine cells of the pancreas, pancreatic neuroendocrine neoplasms (PNENs) arise from pancreatic neuroendocrine cells. The concurrent presence of an exocrine pancreatic tumor and a pancreatic neuroendocrine tumor is referred to broadly as a pancreatic collision tumor. In cases where the lesions are spatially distant, they are termed as multiple primary tumors, a relatively uncommon occurrence. For both, surgical radical resection contributes to improved prognosis. Therefore, accurate evaluation of factors such as tumor number and localization is essential to determine the necessity of radical resection. However, compared to solitary tumors, this often leads to more extensive surgery. We performed subtotal stomach-preserving pancreaticoduodenectomy and distal pancreatectomy (including splenectomy) for a male patient in his 60s with pancreatic head adenocarcinoma and pancreatic tail neuroendocrine tumor (NET) G2. We sought to achieve an insulin-free outcome by preserving the function of the pancreatic body. We report a case where surgical techniques were optimized to enhance postoperative quality of life.

Sclerosing odontogenic carcinoma(SOC)is a rare malignancy first reported by Koutlas in 2008 and was classified as an odontogenic carcinoma according to the World Health Organization(WHO)classification in 2017. In this report, we describe a rare case of SOC in the maxilla of a patient who underwent radical tumor resection via partial maxillectomy and immediate reconstruction using an ulnar forearm flap.

A male in his 70s underwent laparoscopic-assisted high anterior resection and D2 lymph node dissection for rectal cancer (pT3, pN1a, M0, fStage ⅢB)3 years ago. Postoperative adjuvant chemotherapy was not administered due to diabetic nephropathy. Three years post-surgery, plain CT and PET-CT revealed recurrent liver metastasis at the bifurcation of the anterior and posterior liver segments. Right hepatic lobectomy was planned following portal vein embolization, as his ICG R15 was 18.9%, indicating insufficient residual liver volume after resection. To avoid frequent contrast-enhanced CT scans due to low renal function, 4D flow-MRI was performed before portal vein embolization and on the third day post-embolization to measure portal blood flow velocity and volume. These measurements were applied to the estimated residual liver volume formula to predict the residual liver volume 28 days later. The predicted residual liver volume on the 28th day was 469 mL(64%), and CT volumetry performed on the same day showed a volume of 471 mL. Right hepatic lobectomy was performed without worsening liver or kidney function. This case report demonstrates that using 4D flow-MRI can accurately predict the residual liver volume after portal vein embolization, enabling safe curative resection in patients for whom contrast-enhanced CT is challenging due to renal impairment.

Cholangiocellular carcinoma(CoCC)is a rare form of primary liver cancer. We report 2 cases of cholangiocellular carcinoma(CoCC). Case 1: 66-year-old male. He was initially diagnosed as a suspected hepatic hemangioma and followed up, but 5 months later, contrast-enhanced MRI showed an increasing trend, and he was diagnosed as intrahepatic cholangiocarcinoma and underwent surgery. Case 2: 73-year-old female. She was suspected to have hepatic hemangioma. Eight months later, contrast-enhanced MRI showed an enlargement of 20 mm in size, which led to suspicion of hepatocellular carcinoma or intrahepatic cholangiocarcinoma, and surgery was performed. The pathological diagnosis of both patients was CoCC.

A 42-year-old male was referred to our hospital for epigastric and back pain. Following a diagnosis of acute pancreatitis, abdominal CT revealed a low-density tumor measuring 15 mm in diameter in the pancreatic body. Endoscopic retrograde pancreatography showed narrowing of the main pancreatic duct, and cytology of pancreatic juice indicated class Ⅲ. Given the strong suspicion of pancreatic cancer, a distal pancreatectomy was performed. Pathological examination confirmed spindle cell-type anaplastic carcinoma of the pancreas, categorized as pT2, pN0, M0, and pStage ⅠB. Local recurrence and liver metastasis were observed on postoperative day 72. The tumor progressed rapidly, leading to the patient's death on postoperative day 115. Anaplastic carcinoma of the pancreas has a poor prognosis, emphasizing the urgent need for establishing multidisciplinary treatment.

Conversion surgery means surgery for initially unresectable tumors which are converted to resectable tumors by multidisciplinary treatment. Since the introduction of highly effective drug therapies including immune checkpoint inhibitors for hepatocellular carcinoma(HCC), conversion surgery for HCC has become a common experience. Recently, the Japanese Expert Consensus 2023 have reported on the oncological criteria of resectability for HCC, allowing us to use common terms to describe unresectable HCC, which had been ambiguously defined in the past. HCC cases are classified into 3 criteria, based on the tumor number and size, the degree of vascular invasion, and the degree of extrahepatic involvement. The 3 criteria are R(resectable; oncological status for which surgery alone may offer clearly better survival outcomes compared to the other treatment), BR1(borderline resectable 1; oncological status for which surgical intervention as a part of multidisciplinary treatment may offer survival benefit), and BR2(borderline resectable 2; initially unsuitable for resection: oncological status for which efficacy of surgery is indeterminate and surgical indication should be carefully determined under the standard multidisciplinary management of HCC). Whether conversion surgery improves prognosis under the assumption that nonsurgical treatment such as drug therapy has been successful is a question for further investigation.

Pancreatic cancer is known as a disease with an extremely poor prognosis. Although surgery is the only curative treatment, most pancreatic cancer is already advanced at the time of diagnosis. With advances in multidisciplinary treatment such as chemotherapy, radiation therapy, and heavy-ion therapy, more cases of unresectable(UR)pancreatic cancer are being treated with surgery in recent years. Therefore, the term"conversion surgery"has been newly included in the 8th edition of the General Rules for Study of Pancreatic Cancer, and the treatment strategy for UR pancreatic cancer has entered a new phase. Conversion surgery for UR-LA pancreatic cancer is expected to be effective as the indications for chemoradiation and heavy-ion radiation therapy expand. On the other hand, UR-LA pancreatic cancer is not only a locally advanced disease but also a systemic disease, and there have been reports of patients with early postoperative recurrence, so the indication for surgery remains a controversial field. Furthermore, there are increasing reports of conversion surgery for UR-M pancreatic cancer. There are concerns about complications and increased mortality due to extended resection, and early recurrence, so usefulness is not clear at present. Among UR-M, positive peritoneal washing cytology(CY1)is considered to be a preliminary stage of peritoneal dissemination, and is now treated as distant metastasis since the 8th edition of General Rules. CY-positive pancreatic cancer is easier to control than other distant metastases, and CY-negative conversion is expected to be equivalent to that of patients with CY0 at the initial diagnosis. Further evidence for multidisciplinary treatment, including conversion surgery, is expected to be accumulated.

Conversion surgery for gastric cancer is defined as surgery for tumors with distant metastases that are technically or oncologically unresectable at diagnosis, with the aim of achieving R0 resection after chemotherapy. However, there is no randomized controlled trial evidence comparing conversion surgery with continued chemotherapy at the stage of response to chemotherapy. In addition, there are no recommendations on appropriate targets, timing of surgery, extent of resection, pre-and post-operative chemotherapy regimens or duration of chemotherapy, which are issues that need to be resolved. A randomized controlled phase Ⅲ trial is currently underway to address these clinical questions, and it is hoped that this will provide some answers to the long debated significance of conversion surgery.

We report a patient achieving curative resection of synchronous pancreatic and rectal cancers with neoadjuvant chemotherapy. A 71-year-old man was diagnosed with pancreatic head cancer and rectal cancer on close examination for epigastralgia. Abdominal computed tomography showed the pancreatic head cancer had semi-peri-circumferential abnormal invasion into the superior mesenteric vein(SMV), so we diagnosed the tumor as borderline resectable(BR)pancreatic cancer. Colonoscopy revealed a type 1 tumor in the rectum, and biopsy detected a well-differentiated adenocarcinoma. We administered mFOLFIRINOX as preoperative chemotherapy for BR pancreatic cancer, but there was no effect. After the change to GnP, the tumor was reduced and the extent of SMV involvement was also reduced, so pancreaticoduodenectomy(PD)was performed. There was no portal vein invasion of the tumor and R0 resection was achieved. Two months after PD, laparoscopic low anterior resection was performed for rectal cancer. The patient's postoperative course was uneventful, and he had no recurrence in 8 months.

A 73-year-old woman, taking antiviral medication for hepatitis B virus, underwent radiofrequency ablation(RFA)for hepatocellular carcinoma(HCC)in the anterior segment of the liver. Six months, 24 months, and 32 months after the first treatment, RFA was performed for non-local recurrent HCC in segment 4, segment 5, and segment 5, respectively. Nine years and 7 months after the first RFA, a new lesion in the liver, close to the location of the first lesion, was detected on CT and MRI. Simultaneously, a tumor with a diameter of 9 mm was detected in the neck of the pancreas. Laparoscopic anterior segmentectomy of the liver was performed, followed by laparoscopic middle pancreatectomy 10 days later. Pathological study of the specimen revealed biloma in the region of the first RFA and a tumor close to the biloma consisted of HCC partially mixed with cholangiolocellular carcinoma, which is classified as combined hepatocellular-cholangiocarcinoma in the 5th edition of the WHO classification. The tumor in the neck of the pancreas was a poorly differentiated adenocarcinoma without lymph node metastasis. The patient has remained alive for 18 months post-surgery, without recurrence. It is difficult to differentiate HCC from cholangiolocarcinoma or combined hepatocellular-cholangiocarcinoma. Therefore, in case of multiple liver cancers, the intermingling of those tumors should be considered.

An 81-year-old woman was diagnosed with a tumor in the pancreas, detected on CT and MRI. The tumor was 12 mm in diameter and located close and in the distal side of the branch duct-type intraductal papillary mucinous neoplasm(IPMN)in the pancreas head observed for 4 years. Pancreatic ductal adenocarcinoma derived from IPMN was suspected and pylorus-preserving pancreatoduodenectomy was performed. The immunohistological diagnosis of the tumor using a resected specimen was diffuse large B cell lymphoma of the pancreas. After surgery, chemotherapy was not performed because of the patient's decision, but 2 years later, relapse of malignant lymphoma was suspected because of swelling of the bilateral adrenal glands on MRI. R-CHOP immunochemotherapy was started, but seven months later the patient died of lymphoma involving the central nervous system. Primary pancreatic lymphoma(PPL)is a rare disease representing 0.6% of extranodal lymphoma. Many cases of PPL are large, and small lesions under 2 cm in diameter are extremely rare. Furthermore, PPL associated with IPMN has never been reported. The pancreatic tumor close to the IPMN is difficult to diagnose differentially from adenocarcinoma on radiological findings. However, nonsurgical biopsy of the tumor in the pancreas is sometimes challenging if associated with IPMN.

A 40-year-old woman was diagnosed with ipsilateral breast tumor recurrence in the conserved breast 1.5 years after undergoing partial mastectomy for right breast cancer at another hospital. She was referred to our hospital at 19 weeks of gestation. At 21 weeks, total mastectomy of the conserved breast with sentinel lymph node biopsy was performed. The postoperative pathological diagnosis was invasive ductal carcinoma mixed with squamous cell carcinoma. AC chemotherapy was initiated at 33 weeks, and she gave birth by cesarean section at 39 weeks. Postpartum, EC therapy followed by paclitaxel therapy were administered. Currently, she is on endocrine therapy, with no new recurrence observed for 3 years after surgery. Pregnancy-associated breast cancer is rare, accounting for approximately 1% of all breast cancers, and there are few reports on the treatment of local recurrence or distant metastasis during pregnancy. This case, involving breast-conserving surgery recurrence during pregnancy, highlights the importance of careful decision-making and treatment strategies tailored to individual cases, considering the safety of both mother and fetus through multidisciplinary collaboration.

Herein we report on a case of gastric GIST that recurred locally 11 years after surgery, which was successfully resected. The case concerned a male patient in his 70s. In March 2011, the patient underwent proximal gastrectomy for a submucosal tumor in the gastric cardia. The patient was diagnosed with high-risk GIST based on the pathological findings and was treated with imatinib as postoperative adjuvant therapy for 3 years. The patient then continued follow-up as an outpatient. A follow-up CT scan performed in March 2022 showed a mass shadow on the ventral side of the esophagogastric anastomosis, and a biopsy revealed a diagnosis of GIST. The tumor was resected locally as a recurrent gastric GIST.

A 76-year-old man with sigmoid colon cancer and gastric cancer was referred to our hospital because of severe anemia. Computed tomography revealed peritoneal dissemination and lung metastasis. For diagnoses of cStage Ⅳa sigmoid cancer and cStage ⅣB gastric cancer, palliative laparoscopic sigmoidectomy and distal gastrectomy were planned in order to avoid tumor hemorrhage and intestinal obstruction. Intraoperative findings suggested cancer dissemination on the pelvic peritoneum, thus laparoscopic Hartmann's procedure and distal gastrectomy were performed. The final diagnosis was sigmoid colon cancers, ①pT4, ②pT2N2aM1c2(P2, PUL1), pStage Ⅳc and gastric cancer, pT4aN1M1(PER), pStage Ⅳ. The resected specimen showed collision tumors consisting of sigmoid colon cancer(CK20+/CK7-)and dissemination of gastric cancer (CK20-/CK7+)confirmed by immunohistochemistry. Postoperatively, the patient underwent chemotherapy for gastric cancer. We report here a rare case of collision tumor consisting of a sigmoid colon adenocarcinoma and peritoneal dissemination of gastric adenocarcinoma.

A woman in her 50s presented to our department of plastic surgery with a complaint of a nodule in the umbilical region. CT revealed an umbilical tumor and thickening of the anterior wall of the stomach, raising suspicion of gastric cancer with umbilical metastasis. She was referred to surgery. Upper endoscopy identified advanced gastric cancer(type 2)in the greater curvature of the gastric body. PET-CT showed abnormal uptake in the greater curvature of the gastric body, umbilical region, right ovary, and lymph nodes. She was diagnosed with gastric cancer(T4aN3aM1, cStage ⅣB)and underwent chemotherapy. A CT scan after the fourth course showed significant tumor shrinkage, making identification difficult. After 9 months of chemotherapy, upper endoscopy showed marked tumor shrinkage, and CT and PET-CT scans showed that the primary and metastatic lesions were indistinguishable. Exploratory laparoscopy and umbilical biopsy revealed no gross dissemination, and histologically, no tumor cells were found in the umbilical area or ascites. Conversion surgery was deemed appropriate and performed, including distal gastrectomy with bilateral salpingo-oophorectomy. No metastases were found in the lymph nodes or adnexa, and she was diagnosed with ypStage ⅠB(T2N0M0). Adjuvant chemotherapy was administered, and she remains recurrence-free 14 months post-surgery.

A 74-year-old man had locally advanced esophageal cancer with a tracheal diverticulum(cT3brN2M0, cStage ⅢB). After induction chemoradiotherapy, consisting of 3 courses of mFOLFOX therapy and 40 Gy radiotherapy, thoracoscopic radical esophagectomy was performed safely without tracheal injury. Histopathological findings showed that the therapeutic effect was Grade 3. Esophageal cancer has been recurrence-free for 1 year and 3 months after surgery.