Clinical indicators for the incidence of postoperative ileus after elective surgery for colorectal cancer.

BACKGROUND: The occurrence of postoperative ileus leads to increased patient morbidity, longer hospitalization, and higher healthcare costs. No clear policy on postoperative ileus prevention exists. Therefore, we aim to evaluate the clinical factors involved in the development of postoperative ileus after elective surgery for colorectal cancer. METHODS: We retrospectively analyzed patients who underwent elective surgery involving bowel resection with or without re-anastomosis for colon cancer between April 2015 and March 2020. The primary readout was the presence or absence of postoperative ileus. Univariate and multivariate analyses were used to identify pre- and intraoperative risk factors, and the incidence of postoperative ileus was assessed using independent factors. RESULTS: Postoperative ileus occurred in 48 out of 356 patients (13.5%). In multivariate analysis, male sex poor performance status, and intraoperative in-out balance per body weight were independently associated with postoperative ileus development. The incidence of postoperative ileus was 2.5% in the cases with no independent factors; however, it increased to 36.1% when two factors were observed and 75.0% when three factors were matched. CONCLUSIONS: We discovered that male gender, poor performance status, and intraoperative in-out balance per body weight were associated with the development of postoperative ileus. Of these, intraoperative in-out balance per body weight is a controllable factor. Hence it is important to control the intraoperative in-out balance to lower the risk for postoperative ileus.

Heterotopic gastric mucosa in the hilar bile duct mimicking hilar cholangiocarcinoma: report of a case.

We herein report a case of heterotopic gastric mucosa in the hilar bile duct. An asymptomatic 58-year-old male was noted to have mild liver dysfunction in March 2009 during the follow-up for angina pectoris. Abdominal-enhanced CT revealed wall thickening from the upper common hepatic bile duct to the left hepatic bile duct. Endoscopic retrograde cholangiopancreatography (ERCP) showed stenosis at the junction of the left hepatic bile duct. Although the patient's serum tumor markers were all within the normal ranges, the possibility of malignant disease of the biliary tree could not be ruled out. Left hepatectomy with the caudate lobe and resection of the extrahepatic bile duct were performed. Histopathologically, the resected specimen showed a polypoid lesion measuring 2 × 2 cm in size that projected into the lumen of the left hepatic bile duct. Microscopic examination revealed this polypoid lesion to be composed of mucous glands resembling gastric fundic glands, with parietal and chief cells. We also review eight other reports of heterotopic gastric mucosa in the biliary tree previously published in the English literature.

Validation of appendiceal stump invagination in laparoscopic appendectomy.

INTRODUCTION: There are various methods for appendiceal stump dissection, but the necessity for stump invagination remains unclear. This study aimed to assess the efficacy of appendiceal stump invagination in patients with acute appendicitis after laparoscopic appendectomy (LA). METHODS: We enrolled 327 patients with acute appendicitis who underwent LA between 2012 and 2020. Perioperative variables and surgical outcomes were analyzed between the invagination of the appendiceal stump and noninvagination groups. Propensity score-matched analysis (PSM) was performed. RESULTS: More patients experienced severe inflammation and severe intra-abdominal contamination in the noninvagination group than in the invagination group. Patients in the noninvagination group had an older age, higher body mass index, and poorer American Society of Anesthesiologists physical status than the invagination group. Severe inflammation in the noninvagination group was associated with longer hospital stays and poorer postoperative complications than in the invagination group. PSM analysis was performed to minimize bias in the two groups. After PSM analysis, there were no significant differences in surgical site infection, postoperative intra-abdominal abscess, Clavien-Dindo class ≥IIIa, or postoperative stay between the two groups. During the follow-up period, the postoperative adhesive ileus was not significantly different between the invagination and noninvagination groups. CONCLUSION: Invagination of the appendiceal stump during LA is not necessary to prevent short- and long-term complications. Even in cases dissected using a laparoscopic endostapler, the appendiceal stump per se is not related to postoperative adhesive ileus.

Duodenal diverticula perforation caused by an impacted bezoar successfully treated by endoscopic drainage and lithotripsy: A case report and literature review.

Duodenal diverticula perforation due to an impacted bezoar is a rare disease. Surgical treatment is associated with high rates of complications and mortality; therefore, treatment strategies must be carefully decided. Endoscopic treatment offers significant benefits to patients over surgery.

Imaging diagnosis of aberrant proper hepatic and gastroduodenal arteries prior to pancreaticoduodenectomy: A case report.

In hepatobiliary and pancreatic surgery, an understanding of hepatic artery anomalies is of great importance to surgeons. Cases of the proper hepatic artery originating from the superior mesenteric artery and the gastroduodenal artery originating from the celiac trunk are extremely rare. To our knowledge, there are no reports of these arterial variants being diagnosed before hepatobiliary and pancreatic surgery. A 73-year-old woman underwent subtotal stomach-preserving pancreaticoduodenectomy and lymphadenectomy for duodenal carcinoma. Preoperative vascular construction with 3-dimensional computed tomography showed variants of the proper hepatic artery and gastroduodenal artery. The proper hepatic artery originated from the superior mesenteric artery, and the gastroduodenal artery originated from the celiac trunk. Intraoperative findings and preoperative vascular construction from 3-dimensional computed tomography were found to be matched exactly; both the proper hepatic artery and gastroduodenal artery were preserved. By diagnosing a rare arterial variant preoperatively, we were able to perform the surgery safely. In hepatobiliary and pancreatic surgery, understanding any potential variation of the hepatic artery before surgery is crucial to ensure the best patient outcomes.

Laparoscopic resection of schwannoma in the hepatoduodenal ligament: a case report.

BACKGROUND: The occurrence of schwannomas in the hepatoduodenal ligament is rare, and its preoperative accurate diagnosis is difficult. Only few cases have been treated with laparoscopic surgery. CASE PRESENTATION: A 54-year-old man visited our hospital following abnormal abdominal computed tomography findings. He had no complaints, and his laboratory investigations were normal. Abdominal contrast-enhanced computed tomography revealed a tumor with enhancement at the margin of the hepatoduodenal ligament. The abdominal magnetic resonance imaging findings of the tumor showed hypointensity on the T1-weighted images and mixed hypointensity and hyperintensity on the T2-weighted fat-suppression images. Positron emission tomography showed localized accumulation of fludeoxyglucose only in the hepatoduodenal ligament tumor. The patient underwent laparoscopic tumor resection for accurate diagnosis. Histopathologically, the tumor was mainly composed of spindle cells, which were strongly positive for S-100 protein on immunohistochemical staining. The patient was discharged without any postoperative complications on day 5. CONCLUSIONS: Complete tumor resection is essential for schwannomas to avoid recurrence. Laparoscopic surgery is useful for schwannomas occurring in the hepatoduodenal ligament and can be performed safely by devising an appropriate surgical method.

Risk Factors for Anastomotic Leakage after Colorectal Surgery with Double-staple Technique Anastomosis: Impact of the Agatston Score.

OBJECTIVES: Anastomotic leakage is associated with severe morbidity, mortality, and functional defects. Its risk factors remain unclear. However, blood perfusion may be a potential major risk factor. It has been reported that the Agatston score is an index for blood flow perfusion evaluation. Therefore, we evaluated the clinical indicators associated with anastomotic leakage, including the Agatston score, in patients who underwent colorectal surgery. METHODS: We retrospectively analyzed 147 patients who underwent elective colorectal surgery with the double-staple technique anastomosis for colorectal cancer between April 2015 and March 2020. The primary outcome was the presence or absence of anastomotic leakage. Univariate and multivariate analyses were employed to identify pre- and intraoperative risk factors. RESULTS: Of the 147 patients analyzed, anastomotic leakage occurred in 12 (8.16%). Male gender, history of angina and myocardial infarction, preoperative white blood cell count, the Agatston score, extent of bleeding, operation time, and intraoperative fluid volume were significantly related to a higher incidence of anastomotic leakage in univariate analysis. Multivariate analysis demonstrated that the incidence of anastomotic leakage was high in patients with a high Agatston score. CONCLUSIONS: The Agatston score can predict the incidence of anastomotic leakage in patients following colorectal surgery. Thus, perioperative measures to prevent anastomotic leakage are recommended when a high Agatston score is observed. A prospective trial is required to demonstrate, with a high level of evidence, that the Agatston score can be useful as a risk score for anastomotic leakage following colorectal surgery.

Kocuria kristinae infection associated with short bowel syndrome: A case report.

INTRODUCTION: Only a few cases of K. kristinae infection have been reported in the literature. Patients with short bowel syndrome have an increased risk of opportunistic infections due to decreased bowel immunity and the long-term central venous catheter placement. We report a rare case of K. kristinae infection associated with SBS requiring long-term central venous access port placement. PRESENTATION OF CASE: A 70-year-old woman presented with fever of approximately 39 °C to our hospital for examination. She has undergone total hysterectomy and radiation therapy for cervical cancer 36 years ago. Five years ago, she developed multiple small bowel perforations, and a jejunostomy was constructed at the oral end of the perforation and approximately 110 cm from the ligament of Treitz because of the difficulty in dissecting the adhesion. She developed short bowel syndrome, and the central venous port was constructed four years ago due to poor enteral nutrition. K. kristinae was detected in the central venous catheter tip and in two blood cultures. We administered intravenous vancomycin. After seven days of antibiotic treatment, both fever and inflammatory reaction improved, and the blood culture was negative. After 16 days of antibiotic treatment, we performed central venous port construction on the side opposite to the previous site. CONCLUSION: Patients with short bowel syndrome have an increased risk of K. kristinae infections due to decreased bowel immunity and the long-term central venous port, and therefore, these patients should be followed up carefully.

Large hydrocele of the canal of Nuck diagnosed and treated using conventional and laparoscopic methods.

A 49-year-old woman presented to the hospital with a right inguinal swelling. On examination, we suspected hydrocele of the canal of Nuck (HCN) or an appendiceal or retroperitoneal tumor. Surgery for diagnosis and removal of the mass revealed that it was large and located in the preperitoneal cavity, extending into the inguinal ring; so, it was difficult to observe the entire outline of the mass solely using the laparoscopic approach. Therefore, we added the conventional approach with an inguinal incision. This combination of conventional and laparoscopic approaches helped in safe removal of the tumor. The HCN is an unusual developmental condition in women among whom it might cause an inguinal swelling infrequently. In a case with a large HCN, a combined approach using conventional and laparoscopic methods is suggested for better observation of the abdomen and successful resection without perforation of the mass than when using a single approach.

Mixed neuroendocrine-non-neuroendocrine neoplasms of ascending colon: A case report.

INTRODUCTION: Neuroendocrine tumor (NET) that develops in the right-sided colon is relatively rare. Coexistence of adenocarcinoma and NET is extremely rare, and such cases are called mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). PRESENTATION OF CASE: Colonoscopy in an 85-year-old woman for an anemia examination indicated laterally spreading tumor-nongranular (LST-NG) in the transverse colon. Colonoscopy and endoscopic ultrasonography (EUS) showed that the depth of the tumor invasion was deep submucosal. The tumor localization was diagnosed as transverse colon close to the hepatic curvature by enema. Computed tomography (CT) showed no obvious lymph node or distant metastasis. Based on these findings, laparoscopic transverse colectomy with D2 lymphadenectomy was performed. Pathologically, most of the tumor was well-differentiated tubular adenocarcinoma, but some solid follicles of polygonal tumor cells with poor nuclear atypia were observed. Immunostaining was positive for synaptophysin and diagnosed as NET G1. This tumor consisted of adenocarcinoma and neuroendocrine tumor, so we diagnosed it as MiNEN and classified the tumor as fT1N0M0 fStage I (TNM Classification of Malignant Tumors, 8th Edition). Since it was an early stage cancer, postoperative adjuvant therapy was not performed. No recurrence has yet been noted. DISCUSSION: Although MiNEN is extremely rare, the detailed pathological specimen observation and diagnosis are important because long-term follow-up after surgery is needed, as is the adequate selection of postoperative adjuvant therapy. CONCLUSION: It is important to elucidate the mechanisms involved in the coexistence of NET and adenocarcinoma and to apply these findings to future medical care.

Multiple peritoneal dissemination of T2 colorectal cancer without lymph node metastases: a case report.

Most cases of peritoneal dissemination of colorectal cancers are from T3 or T4 tumors. A 61-year-old woman was admitted for examination of a positive fecal occult blood test. Colonoscopy showed an ascending colon tumor that was diagnosed as an adenocarcinoma with massive submucosal invasion. Imaging modality revealed numerous nodules throughout the abdominal cavity. Peritoneal dissemination of the ascending colon or ovarian cancer and pseudomyxoma peritonei were considered in the preoperative differential diagnoses, and laparoscopic ileocecal resection was performed. Intraperitoneal observation revealed numerous white nodules in the peritoneum, omentum and Douglas fossa. Both the nodules and tumor were diagnosed as mucinous carcinoma based on a pathology report. The tumor invasion depth was limited to muscularis propria, and no regional lymph node metastasis was detected. Peritoneal dissemination of the ascending colon cancer was considered. We report a rare case of multiple peritoneal dissemination of T2 colorectal cancer without lymph node metastases.

Inguinal bladder hernia treated using transabdominal preperitoneal approach: A case report.

INTRODUCTION: Inguinal bladder hernia (IBH) is a rare condition that is difficult to diagnose preoperatively based only on physical examination; 16% of IBHs are diagnosed postoperatively due to complications. PRESENTATION OF CASE: We report the case of a 56-year-old man who presented with left inguinal swelling and increased frequency of urination since eight years. Physical examination demonstrated a 6 × 4 cm non-reducible left inguinal bulge with mild tenderness on palpation. Computed tomography revealed a left inguinal hernia containing a portion of the urinary bladder. He was diagnosed with IBH and transabdominal preperitoneal (TAPP) repair was performed. We confirmed a left internal inguinal hernia and incised the peritoneum from the outside of the left inguinal ring. The preperitoneal space was dissected toward the Retzius space, and the prolapsed bladder was examined. The adhesion with the surroundings was carefully dissected and the bladder was reduced into the abdomen. Indigo carmine was injected through a urinary catheter, which confirmed that no bladder damage had occurred. After the mesh was positioned to cover the myopectineal orifice, it was fixed to the Cooper's ligaments, interior side, lateral side, and ventral side. The postoperative course was uneventful, and the patient is now free of symptoms and recurrence two months after surgery. CONCLUSION: TAPP repair is a useful treatment for IBH. Preoperative diagnosis of IBH is important to lessen postoperative complications.

Rectal Arteriovenous Malformation Treated by Transcatheter Arterial Embolization.

An 86-year-old man who presented with frequent hematochezia with mild anemia on blood tests was admitted to our hospital. Colonoscopy exhibited a submucosal tumor-like lesion in the lower rectum. CT and MRI showed blood flow into the lesion, but not tumor component. Angiography of the superior rectal artery and left internal iliac artery showed vascular hyperplasia and nidus. Thus, rectal arteriovenous malformation was diagnosed. If bleeding from arteriovenous malformation was out of control, surgical resection was necessary. However, due to the age of the patient, we performed transcatheter arterial embolization and abdominoperineal resection was not needed. Embolization from the left superior rectal artery, middle rectal artery and inferior rectal artery was performed to control the bleeding and to avoid surgery. After embolization, he was followed up for 10 months in our hospital without recurrence.

A case of duodenal duplication cyst mimicking a pancreatic pseudocyst with intracystic hemorrhage.

BACKGROUND: Duodenal duplication cysts in adults are rare, and a preoperative diagnosis remains difficult because clinical manifestations are nonspecific and variable. We describe a case of a duodenal duplication cyst mimicking a pancreatic pseudocyst with repeated intracystic hemorrhage. CASE PRESENTATION: A 47-year-old male who complained of upper abdominal pain and vomiting was referred to our hospital. He was a heavy drinker and had a past history of hospitalization for alcoholic chronic pancreatitis. Plain abdominal computed tomography (CT) showed a cystic lesion of 7 cm in size in the lumen near the second part of the duodenum. The cystic lesion showed high density inside. Gastrointestinal endoscopy revealed that the lumen of the duodenum was deformed by a submucosal tumor-like mass and the endoscope could not pass through it, but active bleeding was not seen in the lumen of the duodenum. On the fourth day of hospitalization, anemia progressed and contrast-enhanced CT demonstrated a high-density spot on the wall of the cystic lesion. A pancreatic pseudocyst complicated with intracystic hemorrhage was preliminarily considered. Angiography was immediately performed, and a pseudoaneurysm was identified in the branch of the anterior superior pancreaticoduodenal artery (ASPDA). Transcatheter arterial embolization (TAE) was performed. Anemia did not progress after that, and follow-up CT showed reduction in the size of the cystic lesion. Afterward, the same symptoms recurred twice and surgical treatment was performed for the pancreatic pseudocyst with repeated intracystic hemorrhage. Macroscopically, a cystic mass of 5 cm in size was adjacent to the second part of the duodenum on the pancreas side. A pinhole-sized communication was identified between the cyst and the duodenum lumen. Microscopically, the cyst wall was composed of gastric mucosa and shared a common proper muscle layer with the duodenum. Chronic ulcers and erosions were seen in the cyst. Based on these findings, a diagnosis of duodenal duplication cyst was made. CONCLUSIONS: Duodenal duplication cysts in adults have seldom been reported and should be considered as a differential diagnosis for a patient with a cystic lesion adjoining the duodenum.

A Rare Case of Pylephlebitis as a Complication of Cholecystocolonic Fistula.

Pylephlebitis is defined as a septic thrombophlebitis of the portal vein and its tributaries that is associated with multiple suppurative abdominal infections. We report a case of pylephlebitis associated with a cholecystocolonic fistula (CCF). A 41-year-old man presented with upper abdominal pain and anorexia for 1 month. Abdominal contrast-enhanced computed tomography (CT) revealed thrombosis in the left and anterior branch of the portal vein and thickening of the walls of the portal vein and periside portals. The gallbladder was collapsed and pneumobilia was seen in the biliary tract. Blood culture was positive for Streptococcus anginosus. A diagnosis of thrombophlebitis of the portal vein associated with CCF was made, and the patient was immediately managed with an intravenous broad-spectrum antibiotic and anticoagulation. After the portal vein thrombosis (PVT) propagation and inflammation had subsided, cholecystectomy and partial resection of the transverse colon were performed. Pylephlebitis is rare but is a life-threatening complication of intra-abdominal infection. A high index of suspicion is required, and a CT scan should be performed immediately for an early diagnosis and appropriate treatment.

Acute diffuse peritonitis due to spontaneous rupture of a primary gastrointestinal stromal tumor of the jejunum: A case report.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Overt peritonitis caused by GIST rupture is very uncommon. Three types of GIST rupture have been described: closed perforation due to abscess (abscess type), hemoperitoneum leading to rupture of the hematoma capsule in the tumor (hemoperitoneum type), and perforation of the digestive tract via a fistula leading to central necrosis of the tumor (bowel perforation type). This report describes a patient with spontaneous tumor rupture and diffuse peritonitis, a variant of the bowel perforation type of GIST rupture. PRESENTATION OF CASE: A 74-year-old man presented with symptoms of vomiting and abdominal pain. Computed tomography (CT) scan revealed an approximately 10×7-cm mass in the pelvis with free air and fluid collection. Emergency laparotomy revealed a tumor in the jejunum, which was ruptured with a hole measuring 5mm in diameter. The tumor and part of the jejunum were resected. Immunohistochemically, the mass was diagnosed as a GIST originating from the gastrointestinal tract. Despite chemotherapy with imatinib mesylate, the patient died 22 months after surgery. CONCLUSIONS: This report describes a patient with acute diffuse peritonitis due to spontaneous rupture of a primary GIST of the jejunum.

A colovesical fistula with a persistent descending mesocolon due to partial situs inversus: A case report.

INTRODUCTION: Situs inversus viscerum, a congenital condition in which the visceral organs are a mirror image of their normal physiological positions, could be total or partial. Persistent descending mesocolon (PDM) is a congenital anomaly that is asymptomatic because of its short length. PDM causing intestinal obstruction is a known clinical complication. PRESENTATION OF CASE: A 74-year-old woman presented with pneumaturia and enteruria for two months, and recurrent cystitis for a month. An enhanced computed tomography (CT) showed air in the bladder along with sigmoid colonic diverticula adherent to it, suspecting a fistula. The CT also showed partial situs inversus with the common hepatic artery, and left colic artery arising abnormally from the superior mesenteric artery (SMA). Minimally invasive endoscopic closure using the over-the-scope clipping system was difficult because of thickening and scar tissue due to chronic inflammation from diverticulitis. Thus, a sigmoidectomy was performed to close the fistula. Intraoperatively, we noted an abnormally fixed descending mesocolon. An emergency reoperation was performed on the sixth postoperative day owing to an anastomotic leak. Suture failure was attributed to these congenital abnormalities due to insufficient blood flow from an absent marginal vessel and a high endocolonic pressure by adhesions. Sigmoid colon re-resection and maturation of an ileostomy was performed. The patient had no specific postoperative complications, and the ileostomy was closed after three months. CONCLUSION: We report an extremely rare case of colovesical fistula due to a PDM in a patient having partial situs inversus with abnormal branches originating from the SMA.

A case of pancreatic schwannoma showing increased FDG uptake on PET/CT.

INTRODUCTION: Schwannomas are neoplasms originating from Schwann cells in nerve sheath, but pancreatic schwannomas are rare. PRESENTATION OF CASE: A 59-year-old female incidentally pointed out a 2-cm-sized solid mass in the pancreas head by computed tomography (CT) which was performed for other reasons. Magnetic resonance imaging (MRI) showed a mass with hypointensity on T1-weighted images and a heterogenous hyperintensity on T2-weighted images. Magnetic resonance cholangiopancreatography (MRCP) showed no abnormal findings in the main pancreatic duct. The mass of the pancreas head showed a significantly increased uptake on fluorin-18 fluorodeoxyglucose positron emission tomography CT (FDG-PET/CT). Based on the radiological findings, a malignant potential tumor was preliminarily considered. Subtotal stomach-preserving pancreatoduodenectomy (SSSPD) was performed to make a definite diagnosis. The resected specimen showed a well-encapsulated circumscribed mass, measuring 2.0cm, in the pancreas head. Histopathological examination revealed proliferation of spindle cells showing interlacing and palisading patterns in the tumor. The proliferating cells showed no atypia and few mitoses. Immunohistochemically, the spindle cells were positive for S-100 protein. The Ki67 labeling index was approximately 2%. Based on these findings, a diagnosis of benign schwannoma of the pancreas was made. CONCLUSION: Although pancreatic schwannoma is a rare neoplasm, it is important to take into account this tumor in the differential diagnosis of pancreatic tumors. In addition, we should be aware that FDG-PET/CT shows abnormal accumulation in a benign pancreatic schwannoma.

Appendicitis complicated by appendiceal metastasis via peritoneal dissemination from lung cancer.

Peritoneal disseminations from lung cancer are difficult to detect during the patient's clinical course. Therefore, complications of this condition are unclear. We report a case in which peritoneal dissemination from lung cancer complicated appendicitis. A 74-year-old man with lung cancer who was receiving maintenance therapy presented at our hospital because of abdominal pain. It was the seventh day after the 14th cycle of maintenance therapy with bevacizumab. He was diagnosed with acute appendicitis. The resected appendix showed acute appendicitis complicated by appendiceal metastasis from lung cancer. Adenocarcinoma was observed predominantly in the serous membrane from the neck to the tail of the appendix. The distribution of the adenocarcinoma was diffuse. Peritoneal dissemination was considered the route of metastasis. He was admitted to the palliative care unit 10 months after appendectomy. Appendiceal metastasis via peritoneal dissemination from lung cancer complicated appendicitis in our patient who had been receiving bevacizumab.

A mixed adenoneuroendocrine carcinoma of the pancreas: a case report.

A tumor consisting of an adenocarcinoma component and a neuroendocrine carcinoma component, with each component accounting for at least 30% of the tumor, is defined as a mixed adenoneuroendocrine carcinoma (MANEC). We report a case of MANEC of the pancreas. A 63-year-old man presented with hyperglycemia and was referred to our hospital for further examination. Abdominal contrast-enhanced computed tomography (CT) revealed a mass of 2 cm in size in the pancreas head with portal vein narrowing. Fluorin-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) CT revealed increased accumulation in the mass of the pancreas head. Endoscopic retrograde cholangiopancreatography (ERCP) showed severe narrowing of the main pancreatic duct. Cytological analysis by endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) suggested a neuroendocrine tumor. Under the diagnosis of neuroendocrine tumor, pancreaticoduodenectomy with portal vein resection and regional lymph node dissection was performed with curative intent. Histological examination revealed that the tumor consisted of two cell populations. One was well- to moderately differentiated tubular adenocarcinoma. This cell component accounted for 45% of the whole tumor. The second component was non-adenocarcinoma cells arranged in a nest, and the cells had round nuclei, abundant cytoplasm, and coarse chromatin. The Ki67 labeling index was 40%. Immunohistochemically, the adenocarcinoma cells were positive for CEA but negative for chromogranin A (CgA) and synaptophysin (Syn), while the non-adenocarcinoma cells were positive for the expression of CgA and Syn but negative for CEA. Based on the findings, a diagnosis of MANEC of the pancreas was made. Postoperatively, lymph node metastasis and peritoneal dissemination developed rapidly and he died the 6 months after the operation. Due to the small number of reported cases of MANEC of the pancreas, its clinical behavior remains unclear and a standardized management protocol has not been established. Further investigation of more cases of this rare entity is necessary.