Primary extraskeletal osteosarcoma of the breast is extremely rare and has poor prognosis. A 51-year-old woman noticed that the tumor in her left breast had grown rapidly. She had a history of breast cancer on the right 5 years ago. At the same time, a fibroadenoma was detected in her left breast, which was confirmed histopathologically. Re-biopsy specimen analysis revealed that the tumor was probably borderline to malignant phyllodes tumor, metaplastic carcinoma, or stromal sarcoma. The tumor enlarged rapidly during subsequent examinations ; therefore, left mastectomy with sentinel node biopsy was performed as a semi-emergency operation. Pathologically, no epithelial cells were observed in the tumor ; however proliferation of spindle cells and osteoid formations were found. The tumor cells tested positive for Vimentin and CD68 immunohistochemically. A final diagnosis of primary extraskeletal osteosarcoma of the breast was made. The patient underwent adjuvant methotrexate, adriamycin, and cisplatin therapy. The patient has survived with no recurrence reported for 19 months since the operation.

A 73-year-old woman with carcinoma of the right breast showing skin invasion and right axillary lymph node metastasis had been suspected with right lung metastasis at the age of 70 and treated with chemotherapy. She underwent total right mastectomy and right axillary dissection due to persistent bleeding from the breast mass. The condition was diagnosed as invasive ductal carcinoma, pT4bN2aM0, Stage IIIB and was estrogen receptor positive, progesterone receptor positive, and human epidermal growth factor receptor type 2 negative. She was treated with hormone therapy after surgery. A lung mass suspected as metastasis from the breast cancer was identified as squamous cell lung cancer, cT2aN3M1c, Stage IVb and was treated using tyrosine kinase inhibitor. At 72 years of age, the patient underwent thoracoscopic resection of the right lung. After 10 months, right adrenal metastasis was suspected, and right adrenalectomy was performed. However, pathological analysis revealed that the adrenal metastasis was from the breast cancer. Most adrenal metastases from breast cancer involve multiple organs, and solitary adrenal metastasis is rare. In the case of solitary metastasis, local therapy is reportedly effective in improving the prognosis. Moreover, pathological identification of the primary tumor and its pathological features allow us to explore new treatment options and improve the prognosis.

A 71-year-old man was intubated for respiratory failure related to amyotrophic lateral sclerosis (ALS). He presented with epigastric pain, low blood pressure, and bloody aspirate from a nasogastric tube. Contrast-enhanced computed tomography (CT) showed decreased blood flow to the gastric wall and hepatic portal venous air. Emergency laparoscopy was performed for suspected gastric necrosis. During the operation, upper gastrointestinal (GI) endoscopy showed diffuse mucosal erosions, but the gastric serosa appeared intact. Because gastric full-thickness necrosis was ruled out, gastrectomy was not performed. Upper GI endoscopy showed improvement of gastric erosions on postoperative day (POD) 3, and the patient was transferred on POD 65 without any major problems.

Gastric ischemia is rare because of the rich collateral blood supply to the stomach. A case of unexplained gastric ischemia that was successfully treated by exploratory laparoscopy and upper gastrointestinal tract endoscopy is described.

A 63-year-old man, who had undergone distal gastrectomy and Billroth-II reconstruction for a gastric ulcer at the age of 16 years, visited our hospital because of sudden abdominal pain 4 hours earlier. Abdominal CT showed extraintestinal free air and stones in the mesentery of the afferent loop and increased density of fat tissue around the stones. Perforation of the afferent loop was diagnosed, and emergency surgery was performed. A 5 cm lange diverticulum of the afferent loop was perforated by four 1 to 2 cm diameter stones. Partial resection of the afferent loop and drainage were performed. On histopathology, a pseudodiverticulum was seen, and stone analysis showed a calcium salt enterolith. The final diagnosis was perforation of a diverticulum in the afferent loop due to a true enterolith.

A 59-year-old man presented to the emergency room with a complaint of abdominal pain that started the previous day. Contrast-enhanced computed tomography (CT) showed extensive retroperitoneal hematoma mainly in the pancreatic head and stenosis of the celiac artery. He was admitted to the hospital with the diagnosis of retroperitoneal hematoma due to disruption of the pancreaticoduodenal arcade vessels caused by median arcuate ligament syndrome (MALS). Without any evidence of progression of the hematoma on CT images, the patient was discharged on day 9 ; however, he developed vomiting the day after discharge. Because of the deterioration in abdominal symptoms, he presented to the emergency room again on day 14. A CT scan showed duodenal stenosis caused by the retroperitoneal hematoma, and the decision was made to treat him conservatively using a gastric tube. The dyspepsia did not improve, and he underwent laparoscopic gastric jejunal bypass surgery, followed by laparoscopic dissection of the median arcuate ligament. His postoperative course was uneventful. A rare case of MALS that required laparoscopic surgery is presented along with a review of the relevant literature.

Diverticulosis of the small intestine is a relatively rare form of gastrointestinal diverticulosis and is often asymptomatic. There are many reports that preoperative diagnosis of perforation of a small intestinal diverticulum was difficult, but the course was good after surgery. The case of a 97-year-old woman, who lived in a facility, who had a good course after surgical treatment for small intestinal diverticulum perforation, is presented. She was diagnosed with dementia in her hometown and was treated with observation on an ambulatory basis. She was referred to our hospital with chief complaints of abdominal pain and coldness. Her vital signs were normal. The symptoms were not clear. Blood tests showed WBC 2,800/μl and CRP 0.11 mg/dl. Contrast-enhanced computed tomography (CT) showed free air, diverticular perforation of the small intestine was suspected, and emergency surgery was performed. Multiple diverticula were found in the small intestine, and abscess formation was found 70 cm from Treitz's ligament to the anal side. The diagnosis was small intestinal diverticular perforation, and she was treated by partial resection of the small intestine. The histopathological diagnosis was a perforated true diverticulum of the small intestine. Her postoperative course was good, and she was discharged from the hospital on postoperative day 39.

We report a patient with small bowel anisakiasis requiring differentiation from strangulated intestinal obstruction treated with single-incision laparoscopic surgery. A 38-year-old woman was presented with epigastric pain 4 days after she consumed sushi. Intestinal obstruction was suspected based on her history and abdominal radiographic findings. In addition, strangulated intestinal obstruction could not be excluded, so emergency single-incision laparoscopic surgery was performed. An intestinal stenosis was detected 170 cm from the ileocecal region to the oral side, and partial resection of the small intestine was performed. The patient had a good postoperative course and was discharged on postoperative day 5. Postoperative pathological examination of the resected specimen revealed the presence of Anisakis species larvae, and the diagnosis of small bowel anisakiasis was made. Preoperative diagnosis of this disease may be difficult, but if the possibility of strangulated intestinal obstruction cannot be excluded in patients, laparoscopic surgery to examine the abdominal cavity and determine the treatment according to intraoperative findings may be useful.

A 72-year-old woman, who had undergone surgery 54 years earlier, presented with pain around the solar plexus lasting for half a year ; a detailed examination at our hospital revealed anemia and hypoalbuminemia. Furthermore, a colonoscopy revealed lateral anastomosis between the colon and the ileum which might have been done for intestinal obstruction. Her symptoms and examination results led us to suspect blind loop syndrome. A laparoscopic resection of the blind pouch of ileum was performed. After the surgery, the red blood cell count and albumin level improved notably ; moreover, abdominal symptoms also improved. Blind loop syndrome is believed to manifest with dilation of the intestinal tract and stagnation of intestinal contents. Therefore, intestinal bacteria can proliferate anomalously, which causes mucosal damage and symptoms. In our patient, the condition had been asymptomatic for 54 years, but manifested suddenly and worsened within 6 months. Blind pouch resection alleviated the condition. This case would be of precious in considering the disease from various viewpoints.

A rare case of metachronous solitary renal metastasis after radical resection of endocrine cell carcinoma of the ascending colon is reported. An 81-year-old woman underwent open right hemicolectomy and partial resection of the duodenum for ascending colon cancer at the age of 79 years. Pathological findings were por1, pT4b (SI : duodenum), ly1, v1, pN0, fStage IIc, and the avulsion margin was negative. The patient was considered at high risk of recurrence and was treated with postoperative adjuvant chemotherapy with capecitabine. Postoperative 3-month contrast-enhanced abdominal CT showed a hypo-absorptive mass, 15 mm in diameter, in the right inferior pole of the kidney. On postoperative CT at 16 months, the tumor had increased to 20 mm in diameter, but there were no other findings of recurrence. Right nephrectomy was performed. Histopathological findings of the renal mass were similar to those of the ascending colon cancer, and the final diagnosis was renal metastasis of endocrine cell carcinoma of the ascending colon.

In laparoscopic colorectal surgery, preoperative tumor-site marking is important to determine transection lines, where the accuracy and the safety are required. Intraoperative endoscopy or ink injection method has commonly been used. This paper deals with a case of sigmoid colon cancer in which we performed preoperative marking using fluorescent marking clips (ZEOCLIP FS^®, Zeon Medical, Tokyo), identified the tumor location by near infrared camera intraoperatively, and conducted laparoscopic sigmoidectomy.

A 71-year-old man presented with a sigmoid colon polyp at a screening test with lower gastrointestinal endoscopy and was diagnosed with sigmoid colon cancer following EMR with pathological study. As he was found having submucosal invasion with the size of 2400μm, he was referred to our hospital for the purpose of undergoing additional resection. On the day before surgery, we placed four fluorescent marking clips in the vicinity of the anal side of the tumor to make marking of the lesion. During surgery, we could easily confirm these clips by direct vision through the serosa by near infrared camera. No adverse episodes occurred at clipping with the fluorescent clips nor escaping of the clips, and no intraoperative complications occurred. The safety of this method was proved.

The case involved a 63-year-old man who had undergone emergency partial duodenectomy for a duodenal tumor at the age of 43 (2001). On immunohistochemical examination, it was diagnosed as low-risk duodenal gastrointestinal stromal tumor (GIST). The patient who had been asymptomatic until recently was referred to our hospital in 2021 because an enlarged liver mass was found on abdominal computed tomography (CT) in a voluntary health screening. On our examinations, a mass 90-mm in diameter was found in the paracaval portion of the caudate lobe, compressing the portal vein, hepatic vein and inferior vena cava (IVC). A core needle biopsy revealed liver metastasis compatible with the duodenal GIST. We administered the doses of 400mg/day of imatinib for 5 months preoperatively on the concept of neoadjuvant chemotherapy. The tumor had shrunk by 39%. We performed left hepatectomy and caudate lobectomy with resection of the middle hepatic vein on a safe maneuver. The pathological diagnosis was compatible with liver metastasis from the duodenal GIST. We report a case of huge solitary liver metastasis in the paracaval portion 20 years after the resection for duodenal GIST.

A 61-year-old woman underwent screening upper endoscopy for anemia, which showed an extrinsic compression at the antrum of the stomach. Contrast-enhanced CT (CE-CT) showed a solid lesion with abundant blood flow occupying the gallbladder. Apparent serosal invasion or liver infiltration was not observed. Elective surgery was scheduled due to suspected gallbladder cancer, but she developed cholecystitis while waiting for surgery. She underwent emergent open extended cholecystectomy and hilar lymph node dissection. The microscopic examination revealed high-grade intracholecystic papillary neoplasm (ICPN) with massive hemorrhagic necrosis. Since there was neither tumor infiltration at the cystic duct stump nor lymph node metastasis, no additional resection or adjuvant chemotherapy was performed. Four months after the operation, CE-CT for abdominal pain showed multiple liver metastases with intratumoral hemorrhage. Transcatheter arterial embolization (TAE) stabilized her condition, and she was discharged from the hospital. One month after TAE, however, she again developed abdominal pain. On CE-CT, multiple liver metastases had rapidly increased, and intratumoral hemorrhage was noted again. Tumor bleeding was stopped with TAE, but one month later (six months after surgery), she died of cancer.

The patient was a 66-year-old man who had undergone left nephrectomy for left renal cancer four years previously. The pathological diagnosis was clear cell renal cell carcinoma (RCC). Three years after the surgery, a gallbladder polypoid tumor was detected using routine computed tomography. As the size of the tumor increased, laparoscopic cholecystectomy was performed. The specimen was a subpedunculated tumor with a diameter of 17 mm. The histological type of the tumor was clear cell carcinoma ; CD10 and PAX8 were positive, whereas CK7 and CEA were negative, on immunohistochemical staining. We diagnosed the tumor as an RCC metastasis. The patient is alive without recurrence 3.5 years after the cholecystectomy.

In general, RCC tends to metastasize to the lungs, liver, and bones ; gallbladder metastasis is rare. Gallbladder metastasis accounts for less than 1% of all RCC metastases. Only 45 cases have been reported in Japan, and some patients have survived long after cholecystectomy. When a patient with a history of RCC has a gallbladder tumor, the possibility of a metastatic RCC tumor should be considered.

A 77-year-old man was diagnosed with intrahepatic cholangiocarcinoma with portal vein invasion, and underwent left hepatectomy. The pathological diagnosis was liver inflammatory pseudotumor with IgG4-related sclerosing cholangitis (IgG4-SC). No other organ IgG4-related disease or residual disease was observed. The patient was followed up without steroids. Six months later, he was admitted with upper abdominal pain and jaundice. Abdominal computed tomography revealed dilation of the right bile duct and tissue thickening around the bile duct, suggesting fistula formation with the posterior wall of the duodenal bulb. Upper gastrointestinal endoscopy revealed a deep ulcer on the posterior wall of the duodenal bulb. A diagnosis of choledoduodenal fistula due to the recurrence of IgG4-SC and duodenal ulcer was made. Following steroid therapy, the abdominal pain and jaundice disappeared, and tissue thickening around the bile duct improved.

A 68-year-old man who had been receiving treatment for viral hepatitis type C was pointed out having a tumor in the pancreas head. It was finally diagnosed as pancreatic abscess. Since he also developed hepatic abscess as well as recurrent pancreatic abscess, he was referred to our hospital. When 2 months had passed after his first visit, pancreatic leakage associated with purulent discharge erupted at the middle part of a surgical scar of a surgery for duodenal ulcer and was complicated with dermatitis around the crater. He was emergently admitted to our hospital due to massive leakage. A CT scan confirmed the fistula was connected with the pancreas head, and the amylase level of the discharge was as high as 47360 IU/dl. It was diagnosed with pancreaticocutaneous fistula. Despite gauze protection his dermatitis became worse, so somatostatin analogue administration was started on the 2^nd hospital day, but it was withdrawn on the 6^th hospital day due to adverse side effect. Continuous drainage of discharge was thought to be necessary, and on the 9^th hospital day, negative pressure wound therapy (NPWT) was started. His dermatitis rapidly subsided, and in 4 weeks, pancreaticocutaneous fistula was cured. One month later, recurrence was seen, but was cured with one-week NPWT. Thereafter no recurrence has occurred. For pancreaticocutaneous fistula NPWT would be one of an options of treatment.

A 39-year-old woman in her 15th week of pregnancy presented with consciousness disturbance. She was diagnosed with hypoglycemia due to hyperemesis and recovered after glucose administration. She did not develop hypoglycemic symptoms during the remainder of the pregnancy. She gave birth at 38 weeks. Two days after delivery, she lost consciousness again with severe hypoglycemia. Insulinoma was suspected because a fasting test was positive. However, the tumor could not be identified using dynamic CT, MRI, and endoscopic ultrasonography (EUS). Based on the findings of a selective arterial secretagogue injection test, insulinoma of the proximal pancreatic tail was diagnosed using EUS-guided fine-needle aspiration. Spleen-preserving pancreatic tail resection was performed at laparotomy. Insulinoma in pregnancy often develops in the first trimester. Hypoglycemic symptoms become latent due to increased insulin resistance at an advanced gestational age, but they recur as insulin resistance improves after delivery. Insulinoma is rare during pregnancy and is difficult to diagnose, but it should be considered in pregnant women with severe hypoglycemia.

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor, representing less than 1% of all pancreatic malignancies.

A 65-year-old woman presented with complaints of persistent epigastric and back pain for 1 month. Computed tomography (CT) revealed a pancreatic mass with cystic lesions, measuring 5.4×3.3 cm at the head of the pancreas.

Intraductal papillary mucinous carcinoma (IPMC) (cT2N1M0, cStage II B) was suspected, and the patient underwent subtotal stomach-preserving pancreaticoduodenectomy. R0 resection was performed.

Three months postoperatively, the patient's CT indicated multiple liver metastases. She was subsequently treated with GEM+nab-PTX therapy. However, the liver lesions enlarged, and peritoneal lesions appeared after six therapy cycles.

Immunohistochemical staining revealed that her tumor was positive for Bcl-10, which led to the final diagnosis of PACC (pT3N1M0, pStage II B). The patient underwent modified FOLFIRINOX (mFOLFIRINOX) therapy. The liver metastases resolved, and peritoneal lesions reduced after four cycles. At the start of the 6th course of mFOLFIRINOX, the patient's CT revealed a partial response. She was doing well at 11 months postoperatively.