Complications derived from a pancreatectomy are still intractable and remain an unsolved problem despite recent advances in surgical skills and devices. The most intractable complication is pancreatic fistula. The definition of postoperative pancreatic fistula (POPF) described by the International Study Group on Pancreatic Fistula Definition (ISGPF) in 2005 was epoch-making. In spite of good information provided by recent multi-centered studies and cohort studies based on the National Clinical Database (NCD), surgeons are still struggling to overcome and eliminate POPF.

Postoperative pancreatic fistulae (POPF) may cause intra-abdominal abscesses or bleeding. Several studies have reported risk factors associated with POPF, which may be useful to determine the indications for pancreatectomy. Several operative procedures, including pancreatico-gastrostomy, mattress suture, and insertion of a pancreatic stent, have been reported to reduce the rate of POPF. However, the rate of POPF remains high. Therefore, we need to develop new operative procedures to avoid POPF. Due to improved postoperative care, the mortality rate related to POPF has decreased. We should pay attention to pancreatic fistulae after pancreatectomy, especially in high-risk patients, to diagnose and treat this condition earlier.

Delayed gastric emptying (DGE) is a postoperative complication of pancreaticoduodenectomy and occurs in 20 to 25% of patients.

It is sometimes intractable and affects not only patient quality of life but also the prognosis by interfering with administration of adjuvant therapy. DGE is associated with the surgical procedure used for pancreaticoduodenectomy. Pylorus preservation has been proven to be a risk-factor for DGE compared to pyloric resection. Billroth II reconstruction has been reported to be better than Billroth I or Roux-en-Y, and the antecolic route is recommended over the retrocolic route as a route for gastrojejunostomy to limit the occurrence of DGE. However, the precise mechanism of DGE is still unknown, and we should consider the origin of DGE in each patient.

Postoperative hemorrhage (PPH) is one of the most severe complications of pancreatectomy. Bleeding from the gastroduodenal artery after pancreaticoduodenectomy is most frequently encountered. The first-line treatment of delayed PPH was either interventional radiology (coil embolization or covered stenting) or laparotomy. Complete occlusion of arteries by angiographic embolization can lead to intra-hepatic abscess as a result of liver necrosis, ischemia, as well as fatal hepatic failure. To avoid these severe complications, covered stents may represent a better treatment option to preserve arterial flow. The diagnostic procedures employed after development of delayed PPH include endoscopy, angiography, and computed tomography (CT) scan. Timely identification and prompt management are of critical importance to achieve a good outcome.

Despite recent improvements in surgical technique and perioperative care, morbidity after pancreatoduodenectomy still remains high. Occasionally, surgeons encounter biliary complications such as cholangitis, bile stricture, hepatolithiasis and pyogenic hepatic abscess. Preoperative endoscopic retrograde cholangiography, which induces changes in the biliary microbiome and bacterial translocation from the bilioenteric anastomosis can cause postoperative cholangitis. Postoperative refractory cholangitis is associated with biliary strictures and hepatolithiasis. Therapeutic options for the biliary strictures include a percutaneous or endoscopic approach, and a surgical reconstruction. As the success and morbidity rate of each therapy are different, clinicians should choose an adequate treatment strategy in each institution. Since pyogenic hepatic abscesses can contribute to a lethal outcome, proper therapeutic management is required for the best results.

Since the number of patients who undergo pancreatectomy for pancreatic tumors has increased and their prognosis is improving, malabsorption, malnutrition, and steatohepatitis after pancreatectomy have become important clinical issues. Resection of the pancreatic head and duodenum followed by reconstruction after pancreaticoduodenectomy (PD) is associated with the development of nutritional disorders. Nonalcoholic fatty liver disease (NAFLD) often develops after PD due to exocrine dysfunction, malnutrition, and postoperative diarrhea. Therefore, supplementation of exocrine enzymes and zinc are indispensable because some patients develop nonalcoholic steatohepatitis (NASH) from NAFLD. In patients after distal pancreatectomy, the same strategy is relevant because postoperative nutritional disorders often develop when the amount of resected pancreatic parenchyma is significant (over 70%). After total pancreatectomy, intensive nutritional support focusing on sufficient carbohydrate supplementation is essential. However, since postoperative nutritional administration is sometimes difficult in patients with advanced age and/or preoperative nutritional disorders, proximal subtotal pancreatectomy is useful to preserve remnant pancreatic function as long as surgical curability is not compromised.

The long-term survival of patients with pancreatic diabetes after pancreatectomy has improved due to progress in surgical technique, perioperative management and multidisciplinary treatment for advanced cancer.

The pathophysiological state of patients with pancreatogenic diabetes is quite different from Type 2 diabetes and, particularly after total pancreatectomy, more similar to Type 1 diabetes in terms of an absolute reduction in the amount of insulin secreted by pancreatic β cells. However, the fluctuations in blood sugar level is greater than in patients with normal diabetes, accompanied by malnutrition after pancreatectomy and a decrease in glucagon secretion from pancreatic α cells. Therefore, serum glucose control is often difficult in patients with pancreatogenic diabetes.

Especially after total pancreatectomy, the blood sugar level often fluctuates easily even with the current management strategy. Adequate blood sugar control is very difficult. It is necessary to deepen our understanding of the pathophysiological state of patients with pancreatogenic diabetes and to provide appropriate postoperative management.

A 64 year-old man noted jaundice, and was found to have pancreatic cancer, which was treated by radical resection. However, 4 months after resection, his serum CEA level was elevated and a low-density area suggesting metastatic disease was detected in the liver (S7). The patient was treated with FOLFIRINOX chemotherapy and GEM+nab-PTX combination chemotherapy. After chemotherapy, the liver (S7) metastasis was smaller, but 1 month after the tumor resection, a new recurrence was detected in the liver (S6). Treating the new liver metastasis only with chemotherapy was considered difficult, so proton radiation therapy (64Gy) was given. After the radiation therapy, chemotherapy continued for 2 years, and a complete response (CR) was achieved. At 55 months after resection, this patient is alive without new recurrent disease.

A 38 year-old female was evaluated for a pancreatic mass found on abdominal ultrasonographic screening. CT scan revealed an early enhancing tumor in the pancreatic head. MRI revealed that the tumor showed a low signal in the T1 weighted image, a high signal in the T2 weighted image, and a diffusion reduced signal in the diffusion weighted image. EUS showed a 14mm low echoic tumor with a smooth margin and well-defined border near the portal vein. The tumor was strongly enhancing in the early phase of contrast EUS, and EUS-FNA was performed. Cytologic analysis was consistent with a neuroendocrine tumor and a pancreaticoduodenectomy was performed. Hematoxylin and eosin staining showed a Zellballen pattern and immunohistochemical studies were positive for S100 in cells between the tumor clusters, establishing paraganglioma as the final diagnosis. Peripancreatic paraganglioma is rare and it is very difficult to distinguish a paraganglioma from a pancreatic neuroendocrine neoplasm based on imaging studies alone. In an invasive procedure such as EUS-FNA, the blood pressure might be greatly elevated in a patient with a paraganglioma. When EUS-FNA is performed for a tumor rich in blood flow, the differential diagnosis including paraganglioma is very important and we must be ready for acute elevation of blood pressure.

A woman in her 60s was admitted with jaundice. She had a history of resection of a melanotic melanoma in the right paranasal sinus about six months previously. On admission, abdominal CT scan revealed lesions up to 25 mm in the head and body of the pancreas. Those lesions were hypointense on MRI T1-weighted images. This finding was not typical of melanotic melanoma. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed, and a diagnosis of pancreatic metastasis from melanoma confirmed by immunostaining. In this patient, the primary lesion was melanotic but the biopsy specimen from the metastatic lesion contained few melanin granules, which may explain why the pancreatic lesions had such MRI findings. The specimen was evaluated for genetic mutations using the primary lesion in order to select the best therapeutic agent, because there was insufficient tissue from the pancreatic metastasis. The selected drug had little effect, which suggests that the metastatic lesions had a different genetic character than the primary lesion.