Recently, we have shown that after partial hepatectomy (PHx), an increased hepatic blood flow initiates liver growth in mice by vasodilation and mechanically-triggered release of angiocrine signals. Here, we use mass spectrometry to identify a mechanically-induced angiocrine signal in human hepatic endothelial cells, that is, myeloid-derived growth factor (MYDGF). We show that it induces proliferation and promotes survival of primary human hepatocytes derived from different donors in two-dimensional cell culture, via activation of mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3). MYDGF also enhances proliferation of human hepatocytes in three-dimensional organoids. In vivo, genetic deletion of MYDGF decreases hepatocyte proliferation in the regenerating mouse liver after PHx; conversely, adeno-associated viral delivery of MYDGF increases hepatocyte proliferation and MAPK signaling after PHx. We conclude that MYDGF represents a mechanically-induced angiocrine signal and that it triggers growth of, and provides protection to, primary mouse and human hepatocytes.

Introduction The standard operation for carcinoma of the pancreatic head is a partial pancreaticoduodenectomy. Unusual histological findings may occasionally occur in the surgical specimen. We present three unusual histologic diagnoses after pancreaticoduodenectomy. Case presentations In the first case, an 86-year-old Caucasian woman was admitted with abdominal pain and nausea. Preoperative evaluation showed a 3 cm cystic lesion in the head of the pancreas. Pathology revealed a benign multicystic mesothelioma. In the second case, a 45-year-old Caucasian man complained of nausea, vomiting and general malaise for several months. Endoscopic retrograde cholangiopancreatographic examination and a computed tomography scan showed a stenosis of the distal bile duct secondary to a mass in the head of the pancreas and duodenum. Histology showed an adenomyoma of the ampulla. In the third case, a 59-year-old Caucasian man presented with chronic alcoholic pancreatitis. A computed tomography scan revealed a 3.5 cm lesion in the head of the pancreas with cystic and solid components. Pathology showed an undifferentiated carcinoma, sarcomatoid variant. Conclusion Partial pancreaticoduodenectomy is usually performed for ductal adenocarcinomas, neuroendocrine tumors or chronic pancreatitis. Compared to the majority of the above diagnoses, the three cases in our study are very rare. Benign multicystic mesothelioma is a very rare tumor that originates from the peritoneum. Although it demonstrates a benign clinical behaviour, it frequently recurs after resection. Adenomyoma of the bile duct or ampullary region is a very unusual, benign, localized lesion characterized by adenomyomatous hyperplasia. Undifferentiated carcinoma, sarcomatoid variant, is an aggressive tumor and is characterized by spindle cells. As the lesions were suspicious for carcinoma, partial pancreaticoduodenectomy was justified in all three patients. The histologic diagnosis after partial pancreaticoduodenectomy may differ from the preoperative and intraoperative findings. These cases demonstrate that a definitive diagnosis may only be obtained by a pathologic examination of the surgical specimen.

Purpose: Low rectal anastomoses can safely be performed, usually secured by a diverting ostomy. However, in cases of inflammation, extensive scarring, after extensive radiation, or after severe stapler dysfunction the risk for an anastomotic leak may become prohibitively high. We present a novel use for endoluminal vacuum-assisted therapy (EVAT) for otherwise “impossible” low rectal anastomoses. Methods: Our initial series consisted of 14 consecutive patients who underwent prophylactic EVAT treatment due to unsafe low colorectal anastomosis. The vacuum sponge was placed intraoperatively in cases otherwise calling for a Hartmann’s procedure. An open-pored polyurethane sponge was placed prophylactically transanally for a mean duration of 11 days. Patient characteristics, complications, and risk factors were prospectively collected from medical records and analyzed. Results: Between March 2017 and September 2019, we performed this novel technique in 14 patients enabling us to perform an anastomosis. Our collective consisted of 4 female (29%) and 10 male (71%) patients with a medium age of 59 years. Underlying disease was colorectal cancer in 10 patients, ovarian cancer, perforated sigmoid diverticulitis, ischemic colitis and sarcoma in one patient each. Dominant factors putting the anastomosis at extremely high risk were acute inflammation (n = 2), frozen pelvis (n = 2), intraoperative local chemotherapy (n = 2), stapler dysfunction (n = 2), non-closable rectal stump (n = 2), empty pelvis (n = 1) and ultra-low anastomosis (n = 3). Prophylactic EVAT was successful in 92% and gastrointestinal continuity was preserved in all patients. Conclusion: This is the first description of prophylactic EVAT treatment. It seems to be a simple and safe method to enforce the high-risk low rectal anastomosis.

In-situ splitting of the liver before extended resection has gained broad attention. This two-step procedure requires several measures to make an effective and safe procedure. Although the procedure is performed in many institutions, there is no consensus on a uniform technique. The two steps can be divided into different parts and a standardized technique may render the procedure safer and the results will be easier to evaluate. In this paper, we describe a detailed approach to in-situ splitting that allows making both procedures safe, avoids liver necrosis, and is easily reproducible. In the first procedure the portal branches to segments I and IV to VIII are divided, the arterial branches and bile ducts to these segments are preserved and encircled and the parenchyma between segments II/III and IVa/b is divided. This avoids necrosis and bile leaks of segments I and IV and avoids urgent completion operations. In particular, the handling of vital structures close to the dissection line seems important to us. Complete splitting and securing the right and middle hepatic vein will make the second step of this procedure a minimal-risk procedure at a stage where the patient is still recovering from the more demanding first step.