Visceral artery aneurysmal lesion of the omentum - a rare cause of spontaneous fatal intra-abdominal hemorrhage.

We report unexpected death of a 72-year-old man due to a hemoperitoneum (1.9 L of blood in the abdominal cavity). Postmortem examination revealed that the cause of the hemorrhage was an arterial aneurysmal lesion in the greater omentum. The lesion measured 4 × 4 × 6 cm with a generally smooth wall, but with a focal area of rupture within a hemorrhagic region measuring 1 × 2 cm. There was a substantial feeding artery. Histological examination revealed features in keeping with a pseudoaneurysm, but also with some features of a true aneurysm. There was no history of trauma and the rupture of the aneurysmal lesion that had caused the hematoperitoneum was considered to be spontaneous. Prior to his death the deceased had attended hospital for epigastric pain, which was attributed to dyspepsia, but otherwise he had not had symptoms prior to his death.

Omental torsion at the time of COVID-19 in Northern Italy: a case report of conservative management with a review of the pertinent literature.

BACKGROUND AND AIM: In middle-aged men, omental torsion (OT) can be a cause of acute abdomen.The right side of the omentum is longer, heavier and more mobile than the left one and, as a consequence, it can twist more easily on its vascular axis. Consequently, OT localization in the lower right quadrant is more frequent, and therefore it can mimic acute appendicitis clinical onset.In most cases, OT is defined as "primary" in the absence of any other underlying pathologies, or,  rarely, "secondary", when caused by other intra-abdominal diseases such as inguinal hernia, tumors, cysts or post-surgical scarring. To date, clinical diagnosis of OT still remains a challenging one in a preoperative setting and most cases are diagnosed intraoperatively. If diagnosis is correctly achieved preoperatively by adequate imaging examinations, most patients presenting with OT do not undergo surgery anymore. Such considerations gain importance at the time of COVID 19 pandemic, where a conservative management and an early discharge may be preferred owing to in-hospital morbidity after abdominal surgery whenever surgery may be avoided. METHODS AND RESULTS: We present a case of an OT successfully treated in a non-operative manner during COVID-19 outbreak in Norhern Italy and offer a review of the literature that supports such a clinical attitude.  Conclusions:  OT preoperative diagnosis is challenging and is usually achieved by abdominal CT-scan. The suggested OT initial management is conservative, leaving a surgical approach, preferably by laparoscopy, for the 15% of cases not improving with a non-surgical approach.

Cranial transposition and revascularization of autologous omentum: a novel surgical technique for resection of recurrent glioblastoma multiforme.

Glioblastoma multiforme (GBM) patients continue to suffer a poor prognosis. The blood brain barrier (BBB) comprises one of the obstacles for therapy, creating a barrier that decreases the bioavailability of chemotherapeutic agents in the central nervous system. Previously, a vascularized temporoparietal fascial scalp flap (TPFF) lining the resection cavity was introduced in a trial conducted in our institution, in newly-diagnosed GBM patients in an attempt to bypass the BBB after initial resection. In this paper, we report on a new technique to bypass the BBB after re-resection and potentially to allow tumor antigens to be surveilled by the immune system. The study aims to assess the feasibility of performing a cranial transposition and revascularization of autologous omentum after re-resection of GBM. Laparoscopically harvested omental free flap was transposed to the resection cavity by a team consisting of neurosurgeons, otolaryngologists, and general surgeons. This was done as part of a single center, single arm, open-label, phase I study. Autologous abdominal omental tissue was harvested laparoscopically on its vascularized pedicle in 2 patients, transposed as a free flap, revascularized using external carotid artery, and carefully laid into the tumor resection cavity. Patients did well postoperatively returning to baseline activities. Graft viability was confirmed by cerebral angiogram. Omental cranial transposition of a laparoscopically harvested, vascularized flap, into the cavity of re-resected GBM patients is feasible and safe in the short term. Further studies are needed to ascertain whether such technique can improve progression free survival and overall survival in these patients.

Flowthrough Omental Flap for Vascularized Lymph Node Transplant of the Lower Extremity.

SUMMARY: Vascularized lymph node transplantation is a surgical approach for the treatment of chronic lymphedema. However, there is no clinical standard for flap placement nor vascular anastomoses. The authors propose a novel flowthrough configuration for an omental vascularized lymph node transplant in the popliteal space. To prepare the popliteal space for an omental free flap, the medial popliteal fat pad and medial head of the gastrocnemius muscle were debulked. Venous anastomoses were completed with vein couplers, joining the right gastroepiploic vein to the medial sural venae comitantes and the left gastroepiploic vein to the lesser saphenous vein. Arterial anastomoses were hand sewn, joining the right gastroepiploic artery to the proximal medial sural artery and the left gastroepiploic artery to the distal medial sural artery, to create the flowthrough configuration. A retrospective review of patients who underwent this procedure at a single institution was performed. Six patients with chronic lymphedema of the lower extremity underwent vascularized lymph node transplantation from June of 2019 to November of 2020. Five patients underwent at least 3 months of postoperative surveillance, with no postoperative complications reported. In this technique contribution, the authors describe a novel flowthrough configuration for an omental free flap to the popliteal space. The popliteal space offers an aesthetically favorable recipient location when appropriately prepared. The medial sural vessels are ideal recipient vessels for the flowthrough omental flap. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

IL-1ß Impacts Vascular Integrity and Lymphatic Function in the Embryonic Omentum.

BACKGROUND: The chromatin-remodeling enzyme BRG1 (brahma-related gene 1) regulates gene expression in a variety of rapidly differentiating cells during embryonic development. However, the critical genes that BRG1 regulates during lymphatic vascular development are unknown. METHODS: We used genetic and imaging techniques to define the role of BRG1 in murine embryonic lymphatic development, although this approach inadvertently expanded our study to multiple interacting cell types. RESULTS: We found that omental macrophages fine-tune an unexpected developmental process by which erythrocytes escaping from naturally discontinuous omental blood vessels are collected by nearby lymphatic vessels. Our data indicate that circulating fibrin(ogen) leaking from gaps in omental blood vessels can trigger inflammasome-mediated IL-1ß (interleukin-1ß) production and secretion from nearby macrophages. IL-1ß destabilizes adherens junctions in omental blood and lymphatic vessels, contributing to both extravasation of erythrocytes and their uptake by lymphatics. BRG1 regulates IL-1ß production in omental macrophages by transcriptionally suppressing the inflammasome trigger RIPK3 (receptor interacting protein kinase 3). CONCLUSIONS: Genetic deletion of Brg1 in embryonic macrophages leads to excessive IL-1ß production, erythrocyte leakage from blood vessels, and blood-filled lymphatics in the developing omentum. Altogether, these results highlight a novel context for epigenetically regulated crosstalk between macrophages, blood vessels, and lymphatics.

A unique anatomical variation of the vascular supply of the ovary, uterine tube, and uterus from the greater omentum - an anatomical case study.

It is well known that the blood supply of the greater omentum and female internal genital organs are not physiologically connected. There is also no mention of such anatomical variation in anatomical, radiological, or surgical textbooks. Here we present a very rare case report of atypical double arterial anastomosis (the first and second variant artery) between the right limb of the omental arcade of Barkow, uterus, and right ovary, which was found during a routine student anatomical dissection course. It is very challenging to find a proper explanation for the presence of the described anatomical variation; however, we hypothesized that it is based on their common embryonic origin - the mesentery. The first and second variant arteries could be remnants of transient anastomoses or collateral circulation, which were present during embryonic development and persisted until adulthood. Moreover, during our literature review, we noticed that the general description of omental blood supply and its possible variations is relatively poor; therefore, we emphasize the need for more precise knowledge regarding these anatomical parts, which could help surgeons who are performing abdominal or pelvic surgeries in preventing avoidable bleeding.

Alzheimer's Disease: A Decreased Cerebral Blood Flow to Critical Intraneuronal Elements Is the Cause.

Normally, an adequate cerebral blood flow arrives at individual cerebral neurons in which the blood flow augments activity of intraneuronal mitochondria, which is the source of intraneuronal ATP, the energy source of cerebral neurons. With a decrease in cerebral blood flow that can occur as a function of normal aging phenomena, less blood results in decreased mitochondria, decreased ATP, and a decrease in neuronal activity, which can eventually lead to Alzheimer's disease. It has been found that placement of the omentum directly on an Alzheimer's disease brain can lead to improved cognitive function.

The left gastro-omental vessels are able to maintain the entire spleen blood supply / Os vasos gastromentais esquerdos são capazes de manter o suprimento sanguíneo de todo o baço

Abstract The spleen is supplied by blood flow through the splenic artery and vein. The purpose of this communication is to report an ectopic spleen supplied only by reverse flow through the left gastro-omental vessels. A 14-year-old boy presented with pelvic splenomegaly supplied only by the left gastro-omental artery and veins connected to the inferior polar vessels, which were the only vessels communicating with the spleen. After detorsion of the spleen and splenopexy, the spleen returned to normal dimensions. The patient had uneventful follow-up. In conclusion, the left gastroepiploic vessels are able to maintain the entire spleen blood supply.

Resumo O baço é suprido pelo fluxo sanguíneo da artéria e veia esplênicas. O objetivo desta comunicação é apresentar um baço ectópico suprido apenas pelo fluxo sanguíneo reverso proveniente dos vasos gastromentais esquerdos. Um paciente de 14 anos apresentou esplenomegalia pélvica suprida apenas por artéria e veia gastromentais esquerdas, conectadas aos vasos polares inferiores, que eram os únicos presentes nesse baço. Após a distorção do baço e a esplenopexia, o baço voltou às dimensões normais. Não houve intercorrências no acompanhamento do paciente. Em conclusão, os vasos gastromentais esquerdos são capazes de suprir o fluxo sanguíneo de todo o baço.

Vascularized omental lymphatic transplant for upper extremity lymphedema: A systematic review.

BACKGROUND: Vascularized omental lymphatic transplant (VOLT) is an increasingly popular treatment of extremity lymphedema given its promising donor site. While the success of VOLT in the treatment of lymphedema has been reported previously, several questions remain. AIM: To further elucidate appropriate use of VOLT in the treatment of lymphedema, specifically addressing patient selection, harvest technique, and operative methods. METHODS AND RESULTS: A systematic review of VOLT for upper extremity lymphedema was performed. Of 115 yield studies, seven were included for analysis based on inclusion and exclusion criteria. Included studies demonstrated significant reductions in extremity circumference/volume (average volume reduction, 22.7%-39.5%) as well as subjective improvements using patient-reported outcomes. Though studies are heterogenous and limited, when analyzed in aggregate, suggest the efficacy of VOLT in lymphedema treatment. CONCLUSION: This is the largest systematic review of VOLT to date. VOLT continues to show promise as a safe and efficacious surgical intervention for lymphedema in the upper extremity. Further studies are warranted to more definitively identify patients for whom this technique is appropriate as well as ideal harvest and inset technique.

Kynurenine Relaxes Arteries of Normotensive Women and Those With Preeclampsia.

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Inflammation and infarction of adipose tissue: implications in bariatric surgery.

Fat necrosis occurs more frequently in patients who have obesity and diabetes mellitus and is linked to worsening of diabetes. Little evidence is available about surgical complications that are related to inflammation and necrosis of adipose tissue. We report two cases of young women with diabetes who underwent bariatric surgery and had complications resulting from extensive inflammation and necrosis of adipose tissue. The first patient was diagnosed with omental infarction, which is a type of fat necrosis that is rarely associated with obesity and bariatric surgery. The second patient had an intraoperative finding of mesenteric panniculitis, which resulted in an intra-operative change in the choice of bariatric surgery to do a sleeve gastrectomy instead of a gastric bypass. Surgeons who perform surgery on bariatric patients must be aware of complications related to excessive amount of adipose tissue.

Primary omental torsion with massive necrosis A case of uncommon surgical emergency.

A 61-year-old male patient presented to our hospital's emergency department with a history of worsening abdominal pain. The symptoms began as epigastric pain and later localized to the right lower quadrant. On physical examination, there was rebound tenderness mainly in the right lower quadrant and in the right upper quadrant. The laboratory results showed leukocytosis. Abdominopelvic computed tomography scan revealed that a definite twisting on the long axis with three complete counter-clockwise turns was observed in the vascular structures of greater omentum. At operation, the greater omentum was found to be twisted and gangrenous. The infarcted omentum was ligated at the pedicle and excised. Primary torsion of the omentum is one of the uncommon causes of acute abdominal pain. Although rarely diagnosed, the entity is important to the surgeon because it mimics the common causes of the acute surgical abdomen. Omental torsion usually occurs on the right side. Abdominal pain starts suddenly after a heavy meal or hard exercise, and is not accompanied with nausea, vomiting and anorexia. Abdominal computed tomography may show peculiar features suggestive of omental torsion. Treatment consists of ligation and resection of the involved portion of the omentum and recovery is usually rapid, uneventful and complete. Primary omental torsion should be considered in the differential diagnosis of acute abdomen. The surgeon must remain aware of the disease and search for it if, at laparotomy, other adequate cause is not found to explain the symptoms, especially if free sero-sanguineous fluid is found in the peritoneal cavity. KEY WORDS: Acute abdomen, Greater omentum, Omental torsion, Omental infarction, Omental necrosis.

Anomalous Course of Accessory Splenic Arteries in Gastrosplenic Ligament: Case Report and Clinico-Embryological Basis.

Accessory splenic arteries in the gastrosplenic ligament constitute one of the extremely sub-component of abdominal vasculature variations and it is imperative to recognize this anomaly while planning for complex surgeries in the supra-colic compartment. We report the case of accessory splenic arteries in an approximately 50-year-old male cadaver encountered during routine educational dissection. One of them arising from left gastroepiploic artery supplies the spleen in addition to splenic artery. Another variant vessel bifurcated to enter greater omentum and anterior pole of spleen, as discrete branches. The anatomical vascular variation, if recognized during the imaging work-ups for elective surgical procedures could avoid potential iatrogenic blood loss.

Not only fat: omental infarction and its mimics in children. Clinical and ultrasound findings: a pictorial review.

Acute abdominal pain in children is the most common cause of emergency department admissions. Omental infarction is a rare cause of acute abdominal pain in this age group, accounting for approximately 15% of cases in children and 0.024-0.1% of cases of surgery for suspected appendicitis at the same age. Its clinical presentation may mimic similar diseases such as acute appendicitis, epiploic appendagitis, and mesenteric panniculitis. Ultrasound is the modality of choice for the initial evaluation of acute abdominal pain in pediatric patients and it can be used with confidence in the diagnosis and management of omental infarction in children. In this brief review, we focus on the main ultrasound findings and their diagnostic clue for omental infarction and its mimics.

Histopathological findings in a COVID-19 patient affected by ischemic gangrenous cholecystitis.

BACKGROUND: Since its first documentation, a novel coronavirus (SARS-CoV-2) infection has emerged worldwide, with the consequent declaration of a pandemic disease (COVID-19). Severe forms of acute respiratory failure can develop. In addition, SARS-CoV-2 may affect organs other than the lung, such as the liver, with frequent onset of late cholestasis. We here report the histological findings of a COVID-19 patient, affected by a tardive complication of acute ischemic and gangrenous cholecystitis with a perforated and relaxed gallbladder needing urgent surgery. CASE PRESENTATION: A 59-year-old Caucasian male, affected by acute respiratory failure secondary to SARS-CoV-2 infection was admitted to our intensive care unit (ICU). Due to the severity of the disease, invasive mechanical ventilation was instituted and SARS-CoV-2 treatment (azithromycin 250 mg once-daily and hydroxychloroquine 200 mg trice-daily) started. Enoxaparin 8000 IU twice-daily was also administered subcutaneously. At day 8 of ICU admission, the clinical condition improved and patient was extubated. At day 32, patient revealed abdominal pain without signs of peritonism at examination, with increased inflammatory and cholestasis indexes at blood tests. At a first abdominal CT scan, perihepatic effusion and a relaxed gallbladder with dense content were detected. The surgeon decided to wait and see the evolution of clinical conditions. The day after, conditions further worsened and a laparotomic cholecystectomy was performed. A relaxed and perforated ischemic gangrenous gallbladder, with a local tissue inflammation and perihepatic fluid, was intraoperatively met. The gallbladder and a sample of omentum, adherent to the gallbladder, were also sent for histological examination. Hematoxylin-eosin-stained slides display inflammatory infiltration and endoluminal obliteration of vessels, with wall breakthrough, hemorrhagic infarction, and nerve hypertrophy of the gallbladder. The mucosa of the gallbladder appears also atrophic. Omentum vessels also appear largely thrombosed. Immunohistochemistry demonstrates an endothelial overexpression of medium-size vessels (anti-CD31), while not in micro-vessels, with a remarkable activity of macrophages (anti-CD68) and T helper lymphocytes (anti-CD4) against gallbladder vessels. All these findings define a histological diagnosis of vasculitis of the gallbladder. CONCLUSIONS: Ischemic gangrenous cholecystitis can be a tardive complication of COVID-19, and it is characterized by a dysregulated host inflammatory response and thrombosis of medium-size vessels.

Gene-expression profiles of abdominal perivascular adipose tissue distinguish aortic occlusive from stenotic atherosclerotic lesions and denote different pathogenetic pathways.

Perivascular adipose tissue (PVAT) helps regulate arterial homeostasis and plays a role in the pathogenesis of large vessel diseases. In this study, we investigated whether the PVAT of aortic occlusive lesions shows specific gene-expression patterns related to pathophysiology. By a genome-wide approach, we investigated the PVAT transcriptome in patients with aortoiliac occlusive disease. We compared the adipose layer surrounding the distal aorta (atherosclerotic lesion) with the proximal aorta (plaque-free segment), both within and between patients with complete aortoiliac occlusion (Oc) and low-grade aortic stenosis (St). We found that PVAT of the distal versus proximal aorta within both Oc- and St-patients lacks specific, locally restricted gene-expression patterns. Conversely, singular gene-expression profiles distinguished the PVAT between Oc- and St-patients. Functional enrichment analysis revealed that these signatures were associated with pathways related to metabolism of cholesterol, vessel tone regulation, and remodeling, including TGF-ß and SMAD signaling. We finally observed that gene-expression profiles in omental-visceral or subcutaneous fat differentiated between Oc- and St-patients, suggesting that the overall adipose component associates with a different atherosclerosis burden. Our work points out the role of PVAT and, likely, other adipose tissues play in the pathophysiological mechanisms underlying atherosclerotic disease, including the abdominal aortic occlusive forms.

Omental apoplexy: Unravelling the mystery.

INTRODUCTION: To describe cases omental haemorrhage and to review the literature on this topic. METHODS: We describe three cases of spontaneous omental haemorrhage and discuss various management strategies, in an attempt to provide direction for similar cases in the future. RESULTS: A number of case reports of spontaneous or idiopathic omental haemorrhage exist in the literature. These cases are often attributed to an underlying vasculopathy, such as segmental arterial mediolysis (SAM). Appropriate resuscitation is paramount for best outcome. Severe bleeding may require surgery or transcatheter arterial embolisation, which is best performed early if required. Endovascular management using selective catheterisation of the bleeding vessel and embolisation is a minimally invasive alternative to emergent operative intervention. In the three cases we present, endovascular embolisation was performed in two patients, and surgical ligation in a third. Segmental arterial mediolysis is considered the likely aetiology in at least 2 of the 3 cases, based on imaging findings. No further episodes of haemorrhage occurred at follow-up (ranging from 6 months to 2 years). CONCLUSIONS: Acute omental haemorrhage is a rare condition; however, it may be associated with significant morbidity and mortality. CT angiography is the imaging of choice. Management strategies include both endovascular and surgical intervention.