Anatomy of the vitelline vein remnant in human embryos and fetuses.

PURPOSE: To demonstrate the entire course of the human vitelline vein (VV) in specimens after degeneration of the yolk sac. METHODS: Sagittal and horizontal histological sections from 8 embryos and 19 fetuses (gestational age approximately 6-12 weeks; crown-rump length 11-61 mm) were examined. RESULTS: Two types of VV remnants were observed: a long VV on the right superior side of the mesentery of the jejunum (VV1) and a short VV on the left inferior side of the mesentery (VV2). The VV1, observed in 12 specimens, was 20-30 microns in diameter and ran dorsally between the right liver lobe and the jejunum, subsequently merging with an initial superior mesenteric vein on the pancreatic head immediately below the superior portion of the duodenum. The VV2, observed in four specimens, passed dorsally between loops of the ileum on the left side of the mesentery of the ileum and connected to the mesentery. Many of the VVs did not originate from the umbilical cord but suddenly started in the sack of physiological herniation. At 10-12 weeks, after herniation, the VVs originated from the umbilicus and were involved by the expanding greater omentum. CONCLUSIONS: The right-sided and left-sided VVs seemed to correspond to right and left VV remnants, respectively, and both took an upstream course outside the mesentery of the jejunum and ileum. The right VV upstream portion was likely to disappear later than the left one, but the timing of degeneration varied greatly among individuals, depending on the topographical relationship between the right liver lobe and the jejunum.

A randomized controlled trial to evaluate omentum-preserving gastrectomy for patients with T1-T3 gastric cancer.

Although complete omentectomy is traditionally performed in patients with gastric cancer as part of radical gastrectomy to ensure the elimination of micrometastases, the prognostic value of omentectomy during gastrectomy remains unclear. Retrospective studies have shown that the incidence of metastases in the greater omentum is very low in T1-T3 gastric cancer. Thus radical gastrectomy with D2 lymphadenectomy and preservation of the greater omentum may be a proper curative treatment for gastric cancer patients with T1-T3 tumors. The aim of this article is to describe the design and rationale for this prospective, randomized controlled DRAGON-05 trial, conducted to evaluate the prognostic value of omentum-preserving gastrectomy for patients with T1-T3 gastric cancer. Clinical trial registration: ChiCTR2000040045 (ClinicalTrials.gov).

Sympathetic nerve tissue in milky spots of the human greater omentum.

Omental milky spots (OMSs), small lymphoid structures positioned in the greater omentum, are involved in peritoneal immune homeostasis and the formation of omental metastases. Sympathetic nerve activity is known to regulate immune function in other lymphoid organs (e.g. spleen and lymph nodes) and to create a favourable microenvironment for various tumour types. However, it is still unknown whether OMSs receive sympathetic innervation. Therefore, the aim of this study was to establish whether OMSs of the adult human greater omentum receive sympathetic innervation. A total of 18 OMSs were isolated from five omenta, which were removed from 3% formaldehyde-perfused cadavers (with a median age of 84 years, ranging from 64 to 94). OMSs were embedded in paraffin, cut and stained with a general (PGP9.5) and sympathetic nerve marker (TH and DBH), and evaluated by bright field microscopy. A T-cell, B-cell, and macrophage staining was performed to confirm OMS identity. In 50% of the studied OMSs, sympathetic nerve fibres were observed at multiple levels of the same OMS. Nerve fibres were represented as dots or elongated structures and often observed in relation to small vessels and occasionally as individual structures residing between lymphoid cells. The current study shows that 50% of the investigated OMSs contain sympathetic nerve fibres. These findings may contribute to our understanding of neural regulation of peritoneal immune response and the involvement of OMSs in omental metastases.

Unusual duplication and vulnerable intrapancreatic course of the left gastroepiploic artery: a rare anatomical variation.

The left gastroepiploic artery (LGEA) is the least described artery in the medical literature. Unusual variations of this artery might lead to vascular injuries, causing intraoperative bleeding after surgery. We observed rare vascular variations in an adult male cadaver. The left gastroepiploic artery after its origin from splenic artery pierced the pancreatic parenchyma at its posterior surface. After a short intrapancreatic course, the LGEA emerged out from the superior border of the body of the pancreas. LGEA then trifurcated into an omental branch, duplicated LGEA and another branch that continued as the main trunk of LGEA. Main LGEA and duplicated LGEA coursed towards the greater curvature of the stomach. The main LGEA ended by anastomosing with the right gastroepiploic artery, while the duplicated LGEA ended at the greater curvature of the stomach by ramifying into minute branches on the walls of the stomach and gave few gastric branches to supply the stomach and also supplied the greater omentum. This variation was associated with the presence of an accessory splenic artery. Anatomists, surgeons, and radiologists should be aware of such anomalous vascular variations as it could help to minimize complications related to pancreatectomy, omentoplasty, and resection of pancreatic tumors.

Surgical anatomy of the right gastro-omental artery: a study on 100 cadaver dissections.

PURPOSE: The gastro-omental artery (GOA) with the greater omentum (GO) is known for its high quality as a vascular graft, its resistance to infections as an omental flap and for its multiple applications in surgery. A better knowledge of anatomical variations of GO and its vascularization can improve the application in surgery and decrease complications. The purpose of this study was to measure diameters and lengths of the right GOA (RGOA) and study the interindividual variability of these anatomical structures. METHODS: In 100 cadaveric dissections, we carried out dissection of the RGOA and of the GO. In 70 unfixed cadavers, the transillumination technique was used to identify all RGOA branches. In the remaining 30 cadavers, prepared with Winckler's solution, barium sulfate with colored latex was injected. Digital X-ray was used to measure RGOA lengths, internal diameters and the distribution of the omental branches. The gastro-omental vein was also dissected. RESULTS: The mean proximal and distal diameters of RGOA were 2.68 (± 0.39) mm and 0.94 (± 0.24) mm, respectively. The mean length was 244.3 (± 34.4) mm. The thickness of the omentum ranged from 5 to 15.5 mm. The arteria omentalis magna, defined in this study for the fist time as the longest and widest omental branch, was present in 73.3% cases. The trans-omental arch was present in 6% cases. CONCLUSIONS: This morphometric study allowed us to define the vascularization and the anatomical variations of RGOA and GO. This may lead to improvement of applications in surgery and decrease complications.

[Greater omentum flap: Treatment of chronic wounds and seroma: About a case]. / Le lambeau de grand épiploon : traitement des plaies et lymphorrhees chroniques : à propos d'un cas.

INTRODUCTION: Cicatricial complications after abdominal or pelvic surgery are more frequent in obese patients. In this case, infection, seroma and delays in scarring can be extremely difficult to treat. The objective of this technical note is to present an original case of an obese patient operated nine years ago of a hysterectomy by laparotomy and chronically presenting a non-resolving septic seroma despite multiple surgical procedures whose healing could be obtained by a flap of greater omentum. SURGICAL TECHNIQUE: The ideal is to carry out this intervention in a double team with a digestive surgeon in case of intra-abdominal visceral or vascular wound during dissection. The greater omentum flap was raised in a conventional manner over the gastroepiploic artery. A sufficiently wide orifice should be left at the level of the abdominal aponeurosis in order to avoid any compression of the pedicle. Finally, the flap must be spread over the whole surface of the detachment and fixed to the anterior aponeurosis. CONCLUSION: Reliability and vascular and lymphatic richness make the greater omentum flap a very effective method in chronic wound cases associated with important seroma. The scarring obtained in the clinical case presented thus highlights the specific qualities of this flap.

Accessory Spleen in the Greater Omentum: Embryology and Revisited Prevalence Rates.

PURPOSE: To investigate in a large sample the prevalence rates of accessory spleens located in the greater omentum and to explain the embryological background and the vascular supply of this rare congenital disorder. METHODS: Evaluation of the presence of accessory spleens located in the greater omentum was performed in 5 different international anatomical centers investigating a total of 1,045 body donors. Arterial and venous blood supply and the precise location of the respective vasculature within the splenic ligaments are described based on dissection of this rare condition in a male specimen. RESULTS: The reported prevalence rates from 5 different centers were: 0.5% (out of 380 body donors), 0% (out of 230 donors), 0% (out of 200 donors), 2% (out of 200 donors), and 0% (out of 35 donors). The cumulative prevalence rate obtained from 1,045 anatomical dissections was 0.6%. The identified accessory spleen measured 3 × 3 × 2.5 cm and was located in the left upper abdominal quadrant. A vascular stag 7.5 cm in length was identified within the gastro-splenic ligament, containing an artery and a vein piercing the greater omentum from posterior. CONCLUSION: An accessory spleen located in the greater omentum is a rare congenital disorder. Physicians should be aware of the fact that in patients without any representative symptom history a nodular mass located within the greater omentum could be an accessory spleen.

Our initial experience with ventriculo-epiplooic shunt in treatment of hydrocephalus in two centers.

INTRODUCTION: Hydrocephalus represents impairment in cerebrospinal fluid (CSF) dynamics. If the treatment of hydrocephalus is considered difficult, the repeated revisions of ventriculo-peritoneal (VP) shunts are even more challenging. OBJECTIVE: The aim of this article is to evaluate the efficiency of ventriculo-epiplooic (VEp) shunt as a feasible alternative in hydrocephalic patients. MATERIAL AND METHODS: A technical modification regarding the insertion of peritoneal catheter was imagined: midline laparotomy 8-10cm long was performed in order to open the peritoneal cavity; the great omentum was dissected between its two layers; we placed the distal end of the catheter between the two epiplooic layers; a fenestration of 4cm in diameter into the visceral layer was also performed. A retrospective study of medical records of 15 consecutive patients with hydrocephalus treated with VEp shunt is also presented. RESULTS: Between 2008 and 2014 we performed VEp shunt in 15 patients: 5 with congenital hydrocephalus, 8 with secondary hydrocephalus and 2 with normal pressure hydrocephalus. There were 7 men and 8 women. VEp shunt was performed in 13 patients with multiple distal shunt failures and in 2 patients, with history of abdominal surgery, as de novo extracranial drainage procedure. The outcome was favorable in all cases, with no significant postoperative complications. CONCLUSIONS: VEp shunt is a new, safe and efficient surgical technique for the treatment of hydrocephalus. VEp shunt is indicated in patients with history of recurrent distal shunt failures, and in patients with history of open abdominal surgery and high risk for developing abdominal complications.

Ultrasound Elastography for Differentiating Benign from Malignant Thickened Greater Omentum.

OBJECTIVES: To investigate whether ultrasound elastography (UE) is an effective non-invasive diagnostic procedure for evaluating benign and malignant thickened greater omentum. METHODS: Ultrasound elastographic images from 118 patients who underwent ultrasound-guided biopsy for thickened greater omentum from May 2012 to October 2013 were retrospectively analysed. The results were compared with the pathological findings from the biopsies, and evaluated by ROC curve analysis. RESULTS: A total of 93.6% of the benign thickened greater omentum had elasticity scoring of 1 or 2, whereas 93.0% of the malignant thickened greater omentum had elasticity scoring of 3 or 4. The elasticity strain ratios for malignant thickened greater omenta were higher than for benign thickened greater omenta using muscle or fat yielded as reference tissue (P < 0.01). The optimal cut-off point for elasticity strain ratios using fat as reference was 2.6. The sensitivity, specificity, accuracy, and positive and negative predictive values for determining elasticity strain ratios using fat as reference were 83.3%, 90.6%, 86.5%, 92.1%, and 80.6%, respectively, and for elasticity scoring were 95.2%, 96.9%, 95.9%, 97.6%, and 93.9%, respectively. CONCLUSIONS: UE using elasticity scoring or elasticity strain ratios is an effective new non-invasive method for differentiating benign from malignant thickened greater omentum. KEY POINTS: • Elasticity score is an objective method for differentiating greater omentum lesions. • Elasticity strain ratio is another method for differentiating greater omentum lesions. • Fat tissue is better than abdominal wall muscle as reference in elasticity imaging. • UE is a new effective, non-invasive method for diagnosing omental diseases.

Omental leiomyosarcoma with unusual giant cells in a Beagle dog - Short communication.

A 10-year-old castrated male Beagle dog was presented with a 2-month history of intermittent vomiting and abdominal pain. The dog was referred to the Veterinary Teaching Hospital at Iwate University for further evaluation, and a splenic tumour was suspected on the basis of ultrasonography and computed tomography. Surgery identified a large, solid, light-pink mass on the greater omentum with blood-coloured ascites in the abdominal cavity, and resection was performed. Microscopically, the mass comprised spindle-shaped tumour cells and scattered osteoclast-like giant cells. Most spindle-shaped cells were positive for vimentin, desmin, and smooth muscle actin (α-SMA), whereas osteoclast-like giant cells were positive only for vimentin. On the basis of histopathological and immunohistochemical findings, a diagnosis of leiomyosarcoma was made. To the best of our knowledge, this represents the first report of leiomyosarcoma associated with osteoclast-like giant cells developing from the greater omentum in a dog.

Unusual cause of acute abdomen in a child--torsion of greater omentum: report of two cases.

INTRODUCTION: Torsion of the omentum is twisting along its long axis and a rare cause of acute abdomen. Depending on associated conditions, it is classified as primary and secondary. It may mimic different pathologies presenting as acute abdomen, most common of them being acute appendicitis. Current choice for management of omental torsion is laparoscopic surgery. CASE PRESENTATION: We present two cases of omental torsion of two boys who presented with abdominal pain, nausea and vomiting and underwent emergency laparoscopy. CONCLUSION: Omental torsion is very rare, and its diagnosis is usually made only after surgery. At laparoscopy, omental torsion is suspected when the appendix is normal and the symptoms and findings of torsion are present. Laparoscopy is a safe and effective approach for the diagnosis and management of omental torsion, with the advantages of reduced postoperative pain and hospital stay.

Further exploration during open appendicectomy; assessment of some common intraoperative findings.

OBJECTIVE: Very few studies are available to relate the final histology of excised appendix with the detailed intra-operative findings during appendectomy, both open and laparoscopic. This study was aimed to correlate the histological features of appendix specimen with the intra operative findings at open appendicectomy (OA) in a bid to determine when to change the planned procedure to include further exploration. Methods : A prospective study that observes the condition of the greater omentum (GO), the vermiform appendix and peritoneal exudates at all OA done for uncomplicated appendicitis. Histological examination of the appendices done using the H&E stain. Results : Eighty-five patients had emergency open OA, their(') ages range from 6 to 62 yrs (median = 23yrs). Histology showed 7 normal appendix (HNA), 56 acute (HAA) and 22 "non acute" appendicitis (HNAA). Negative appendicectomy rate was 8.2%. The GO was sighted more in patients with HAA than HNAA (p=0.00015) and also significantly more inflamed in the former (p=0.00028). It is not significantly inflamed in those with HNAA (p=0.945). The negative predictive value (NPV) of absent GO is 35.7% while the positive predictive value (PPV) of sighted normal GO and inflamed GO are 92.8% and 100% respectively. The PPV and NPV of presence of pus for diseased appendix are 95.8% and 9.8% respectively while those of excess fluid are 94.8% and 10.8%. The PPV and NPV of macroscopic assessment of the appendix for inflammation are 97% and 45.5% respectively giving the diagnostic accuracy of 90.6%. A significant trend of increasing probability of histologically inflamed appendix with increasing severity of macroscopic feature was seen (X(2) = 004 df=1, p<0.005). CONCLUSION: High positive and low negative predictive values are similar for all the three parameters assessed. The macroscopic appearance of the appendix has a predictive likelihood ratio for further exploration.

Parasitic leiomyoma of the greater omentum: a case report and literature review.

Parasitic leiomyomas (PL), also known as free leiomyomas, which occur outside the uterus and rarely happen in clinical practice. They are usually reported in women of reproductive age who underwent hysterectomy or myomectomy and frequently present with symptoms such as abdominal pain and distention. In fact, it is hard to determine the nature of the mass according to the imaging examination and clinical manifestation. At present, the most common treatment involves an abdominal or laparoscopic surgery in order to remove the mass and perform the next step of treatment based on the histological diagnosis. In this case report, we describe a 35-year-old woman with a 12.4 × 9.3 × 9.8 cm3 PL with blood supply from the greater omentum. Considering the prolonged menstruation of the patient, she underwent the hysteroscopic and laparotomy exploration. The mass was confirmed as smooth leiomyoma with necrosis by the immunohistochemical examination. The patient had a good recovery and being discharged seven days after the surgery. The patient is still in the follow-up.

Case report: A rare case of omental extrarenal rhabdoid tumor and review of the literature.

Extrarenal rhabdoid tumor of the greater omentum is extremely rare, with only sporadic reports and limited documentation of its ultrasonographic findings. Here, we report a case of an extrarenal rhabdoid tumor of the greater omentum in a 16-year-old girl and review the relevant literature. It was found that the disease mainly occurred in female children and adolescents, and mainly manifested as lower abdominal pain and a large abdominal cystic or solid hemorrhagic mass. The clinical characteristics include a high degree of malignancy and mortality. Ultrasound shows some malignant features, but it is not specific; thus, it is easy to be misdiagnosed in the clinic.

Malignant Extrarenal Rhabdoid tumor derived from the greater omentum: A case report and literature review.

BACKGROUND: Malignant extrarenal rhabdoid tumor (MERT) is a rare and highly metastatic tumor, which is more than 75% of patients dying within 6 months of initial diagnosis, and it often leads to misdiagnosis and delayed treatment. CASE: This paper reports a 16-year-old girl who presented with the chief complaint of acute abdominal pain. She underwent laparoscopic exploration and excisional biopsy, then pathological examination and immunohistochemistry revealed "extrarenal malignant rhabdomyoma." One month after operation, she died of intra-abdominal hemorrhage and multiple organ dysfunction. CONCLUSION: MERT were often misdiagnosed and had a poor prognosis. The surgery and chemotherapy are usually beneficial to prolong the survival time of patients with MERT.

Primary Omental Torsion in Children in the Laparoscopy Era: What Have we Learned so far?

BACKGROUND/AIM: Primary omental torsion is uncommon, mimicking appendicitis and other acute abdominal pathologies. It often escapes diagnosis on imaging investigation or conventional open laparotomy. This study aimed to evaluate the effect of laparoscopy on the various parameters of this entity, including incidence, diagnosis, and treatment. MATERIALS AND METHODS: A systematic review was performed, including PubMed and Scopus databases, without a time limit, following the PRISMA principles. A total of 16 articles from January 2000 to December 2023, corresponding to 56 children with primary omental torsion, complied with the research criteria. RESULTS: Primary omental torsion was associated with obesity. Symptoms were right abdomen oriented, often compared to those of acute appendicitis. Preoperative ultrasound displayed low diagnostic accuracy, whereas computerized tomography diagnosed only two thirds of cases. In all patients, the vermiform appendix was normal. CONCLUSION: Laparoscopy affected both diagnosis and treatment of primary omental torsion in children. Easy peritoneal cavity access rendered possible the diagnosis of cases previously discharged as abdominal pain of unknown etiology. Combined with the increased pediatric obesity, it also affected primary omental torsion incidence. The recent pathogenetic theories may be better supported today, as laparoscopy provides a detailed view in situ, and facilitates harvesting of fat tissue from the omentum for molecular investigation. The diagnostic efficiency of laparoscopy is superior to ultrasonography and computerized tomography. Finally, the removal of the ischemic omentum is technically easier compared to the open laparotomy alternative with all the technical difficulties of traction of a vulnerable hemorrhagic tissue through a small incision.

Primary omental infarction - a benign cause of acute abdomen.

Objectives: Omental infarction (OI) is an uncommon cause of acute abdominal pain. A high index of clinical suspicion is required for diagnosis of OI as the incidence is less than 1 %, presenting with abdominal pain. We report primary OI's clinical and radiological profile from a single tertiary care hospital in India. Methods: In this retrospective cross-sectional study, the electronic medical and radiology records of patients with abdominal pain were reviewed over seven years (2015-2022). Variables were systematically collected and analyzed. Results: A total of 22 patients diagnosed with primary OI were included in this study. Male preponderance (63.6 %) was noted with a mean age of 47.45 years (SD ± 13.84; range: 18-72 years). Most patients belonged to class I obesity (according to the Asia-Pacific body mass index classification) with a mean BMI of 26.56 kg/m2 (SD ± 3.21 kg/m2). All patients had abdominal pain as the primary symptom, with a mean duration of 8.64 days (SD ± 10.15; range: 1-42 days). The most common locations of pain were the right hypochondrium (27.3 %) and diffuse (27.3 %), followed by the right iliac fossa (18.1 %). Most (95.45 %, n=21/22) patients were treated conservatively, and only one required surgical intervention. Conclusions: Primary OI is a rare and benign cause of acute abdomen. Obesity is a risk factor but does not correlate with the size or severity of OI. Radiological imaging, like a computed tomography (CT) scan, is essential for diagnosis. A conservative management line should be the first approach in treating primary OI before considering surgical options.

Omental fibroma combined with right indirect inguinal hernia masquerades as a scrotal tumor: A case report.

BACKGROUND: The most common causes of scrotal enlargement in patients include primary tumor of the scrotum, inflammation, hydrocele of the tunica vaginalis, and indirect inguinal hernia; scrotal enlargement caused by external tumors of the scrotum is rare. The patient had both a greater omentum tumor and an inguinal hernia, and the tumor protruded into the scrotum through the hernia sac, which is even rarer. Moreover, omental tumors are mostly metastatic, and primary omental fibroma is rare. CASE SUMMARY: Here, we report a rare case of a 25-year-old young man with scrotal enlargement and pain for 3 months. Preoperative examination and multidisciplinary discussions considered intra-abdominal tumor displacement and inguinal hernia, and intraoperative exploration confirmed that the greater omentum tumor protruded into the scrotum. Therefore, tumor resection and tension-free inguinal hernia repair were performed. The final diagnosis was benign fibroma of the greater omentum accompanied by an indirect inguinal hernia. CONCLUSION: This unusual presentation of a common inguinal hernia disease illustrates the necessity of performing detailed history taking, physical examination, and imaging before surgery.

Primary omental torsion with clinical masquerading as acute appendicitis and radiological key for diagnosis.

Omental torsion is a medical condition characterized by the twisting of the omentum along its longitudinal axis, which leads to compromised blood flow. This condition is rarely diagnosed before surgery and can present symptoms similar to other causes of acute surgical abdomen. This report details a case of primary omental torsion initially suspected to be acute appendicitis. The patient was admitted to the hospital with symptoms of lower right quadrant abdominal pain and mild fever. Computed tomography imaging revealed a twisted mass of fatty tissue with surrounding fat stranding changes, but no signs of appendicitis were found, indicating omental torsion. The patient underwent surgery to remove the twisted and necrotic omentum, leading to an improvement in symptoms. This case highlights the challenges in diagnosis and the crucial role of computed tomography imaging in managing this rare condition.

Morphological differences between the lesser and the greater omenta in albino rats.

BACKGROUND: Publications report that all mammals have two omenta, namely, lesser omentum and greater omentum. Basically, these organs, which share the same name except for the adjective "lesser" or "greater," should not differ from each other. However, no clear description of the structure of the lesser omentum, as well as comparative morphological analysis between the lesser and greater omenta have been found in the literature, which necessitates a thorough investigation. Therefore, the aim of our study was to analyze the morphofunctional differences between the greater and lesser omenta in albino rats. METHOD: The experiment involved 20 mature male albino rats, weighing 298,28±7,36 grams. The material for our study were preparations of lesser and greater omenta, fixed in 10 % of neutral buffered formalin. Paraffin sections were stained with hematoxylin-eosin and Van Gieson stain. RESULTS: The findings of the study showed that the greater omentum in albino rats, unlike other derivatives of the omentum (ligaments and mesenteries), represents a free extension (mostly from the greater curvature of the stomach), in the form of an "apron," into a specific depth of the peritoneal cavity, duplicating the serous membrane. This duplication is characterized by the composition of two structurally interdependent formations. These include vascular-fatty arcades, associated with lymphoid nodules known as milky spots, and binding serous-reticular membranes. The findings of the study of the lesser omentum have established that in all cases it is located beneath the liver and becomes visualized only after hepatolifting. It is presented in the form of two ligaments: hepatoduodenal and hepatogastric, which contain two main structured formations, which we called vascular-fatty spurs, between these spurs, serous-reticular membranes are located. CONCLUSION: despite having similar names, the lesser omentum, a derivative of the peritoneum, is fundamentally different. As it is well known, the lesser omentum is represented by ligaments that extend from the liver hilus to the lesser curvature of the stomach and the duodenum. Due to this arrangement, the lesser omentum lacks the mobile activity characteristic of the greater omentum, which plays a crucial role in rapid response to damage in the gastrointestinal tract. Despite sharing the same names, both formations differ in shape, morphological structure, development and function.