Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report

BACKGROUND

The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient.

CASE PRESENTATION

A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up.

DISCUSSION AND CONCLUSION

We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

A randomized controlled trial to compare short-term outcomes following infragastric and infracolic omentectomy at the time of primary debulking surgery for epithelial ovarian cancer with normal-appearing omentum

BACKGROUND

Omentectomy is an important procedure in surgery for epithelial ovarian cancer, but the scope of omentectomy is not recommended in the guidelines. This study was performed to evaluate the benefits and risks of infragastric omentectomy in patients with epithelial ovarian cancer.

METHODS

This trial is a single center prospective study. Primary epithelial ovarian cancer patients with normal-appearing omentum were randomly assigned to either the control or experimental group and underwent infracolic or infragastric omentectomy, respectively. The primary endpoint was progression-free survival. This trial is registered on Chinese clinical trial registry site (ChiCTR1800018771).

RESULTS

A total of 106 patients meeting the inclusion criteria for ovarian cancer were included during the study period. Of these, 53 patients underwent infracolic omentectomy, whereas 53 patients received infragastric omentectomy. Multivariate analysis revealed that infragastric omentectomy could improve the detection rate of omental metastases (OR: 6.519, P = 0.005). Infragastric omentectomy improved progression-free survival significantly for those cases with higher than stage IIB disease (HR: 0.456, P = 0.041). Based on the short-term results, infragastric omentectomy did not cause more perioperative complications.

CONCLUSIONS

Compared with infracolic omentectomy, infragrastric omentectomy may be a more appropriate surgical procedure for stage IIB-IIIC epithelial ovarian cancer patients with normal-appearing omentum.

Vagus nerve signal has an inhibitory influence on the development of peritoneal metastasis in murine gastric cancer

The vagus nerve is the only pathway for transmitting parasympathetic signals between the brain and thoracoabdominal organs, thereby exhibiting anti-inflammatory functions through the cholinergic anti-inflammatory pathway. Despite often being resected during lymph node dissection in upper gastrointestinal cancer surgery, the impact of vagotomy on postoperative outcomes in gastric cancer patients remains unclear. Sub-diaphragmatic vagotomy was performed on C57BL/6 mice. Three weeks later, syngeneic murine gastric cancer cell line YTN16P was injected into the peritoneal cavity, and the number of peritoneal metastases (PM) on the mesentery and omentum compared with control mice. The phenotypes of immune cells in peritoneal lavage and omental milky spots one day after tumor inoculation were analyzed using flow cytometry and immunohistochemistry. Intraperitoneal transfer of 3 × 105 YTN16P significantly increased the number of metastatic nodules on the mesentery in the vagotomy group compared to the control group. The omental metastasis grade was also significantly higher in the vagotomy group. Phenotypic analysis of immune cells in peritoneal lavage did not reveal significant differences after vagotomy. However, vagotomized mice exhibited a notable increase in milky spot area, with a higher presence of cytokeratin(+) tumor cells, F4/80(+) macrophages, and CD3(+) T cells. Vagus nerve signaling appears to regulate the immune response dynamics within milky spots against disseminated tumor cells and inhibits the development of PM. Preserving the vagus nerve may offer advantages in advanced gastric cancer surgery to reduce peritoneal recurrence.

Primary segmental omental torsion, mimicking acute appendicitis

Primary segmental omental torsion (PSOT) is a very rare cause of acute abdominal pain, and it may often imitate the clinical picture of acute appendicitis. In instances of acute abdominal pain without anorexia, nausea, and vomiting, omental torsion should be included in the differential diagnosis. Any misdiagnosis may lead to major complications such as intraabdominal abscesses and adhesions. A 63-year-old overweight man with a body mass index (BMI) of 41 Kg/m2 presented to the emergency department on a remote island with acute abdominal pain. His medical history included type 2 diabetes mellitus managed with insulin, essential hypertension, osteoarthritis, and no previous abdominal operations. He reported a sharp pain originating in the epigastrium and the right hypochondrium that started five days prior. Physical examination revealed rebound tenderness and guarding across the abdomen with a positive McBurney sign. However, the patient did not report vomiting and was not nauseous. Vital signs were as follows: blood pressure 116/56 mmHg, heart rate 98 beats/min, respiratory rate 19 breaths/min, and a temperature of 38.2 0C. Laboratory results showed a white blood cell count of 10.6, neutrophils of 8.11, C-reactive protein (CRP) 74 mg/l, haemoglobin11.6 g/dl, and hematocrit 36.9%. Due to the absence of a radiographer at the hospital during that period, no imaging investigations were conducted. Diagnostic laparoscopy demonstrated diffused hemoperitoneum and necrotic mass at the site of the hepatic flexure. Initially suspected to be an advanced colon cancer, the decision was made to proceed with open surgery. The necrotic segment of the omentum was found at the right superior point of attachment of the omentum to the hepatic flexure. Consequently, the necrotic segment of the omentum was resected. A thorough investigation of the abdominal cavity did not detect any other abnormalities or pathologies. The patient recovered uneventfully and was transferred to the surgical ward. Torsion of the omentum is a very rare cause of acute abdominal pain. This case highlights the necessity of considering PSOT in the differential diagnosis of acute abdominal pain, especially in cases where symptoms are suggestive of appendicitis but diagnostic findings are negative.

Neuroendocrine tumour of the lesser omentum

A man in his early 20s presented to us in the outpatient department with a history of diarrhoea for 4 months. Investigations revealed elevated serum chromogranin levels and an intensely avid lesion in the gastrohepatic ligament in Gallium DOTATATE positron emission tomography (PET). The tumour was excised laparoscopically, and no other lesions were seen. The patient improved clinically and had a normal serum chromogranin level postoperatively. He is currently much improved at the 1year follow-up. We did an extensive workup to look for a primary tumour. It was concluded that it was a de novo tumour arising from the lesser sac. The recommended investigations in case of neuroendocrine tumour (NET) with unknown primary include blood investigations to look for the functional status of the tumour, histopathological examination, including immunohistochemistry, and radiological imaging, which must include a Gallium DOTATATE PET. An isolated NET of the lesser sac has not been reported in the literature.

A protocol for selection in mice of highly metastatic ovarian cancer cell with omental tropism

Preclinical models mimicking spontaneous omental metastasis from ovarian cancer (OC) can benefit the study of anti-metastatic therapies for OC patients. Here, we present a protocol to establish a highly metastatic (HM) mouse model with omental tropism by in vivo selection. We describe the processes of implanting OC cells in the ovaries of mice and obtaining HM sublines from their omental metastases. HM cells can metastasize from the ovary to the omentum within 2 weeks. For complete details on the use and execution of this protocol, please refer to Ying et al.1.

Inguinal hernia leading to omental torsion: Role of CT in differentiating from other clinical mimics - a case report and literature review

Omental torsion is a very rare cause of acute abdomen. Clinically, it mimics other common pathologies such as acute appendicitis, acute diverticulitis and acute cholecystitis. It is therefore no surprise, that it was rarely diagnosed pre operatively before the advent and easy availability of modern imaging techniques. CT scan, in particular, can diagnose omental torsion with confidence pre operatively. This can make conservative treatment possible in cases of primary omental torsion and guide regarding the appropriate treatment in cases of secondary torsion. We present a case of a young male patient who presented to Emergency department with symptoms of acute abdomen. Clinical and laboratory findings were non-specific for any specific cause of acute abdomen. CT scan, however, showed omental fat stranding with whirlpool sign representing omental torsion which was seen to be secondary to left inguinal hernia. Patient was operated in emergency and necrotic omentum was resected and hernia repaired. Post-operative recovery was uneventful.

Ovarian Microcystic Stromal Tumor With Intraovarian Recurrence and Peritoneal and Omental Spread: A Case Report With Morphological, Immunohistochemical, and Molecular Analysis

Microcystic stromal tumors (MCSTs) are rare ovarian stromal tumors. They harbor CTNNB1 or APC mutations, resulting in β-catenin nuclear expression. To date, all MCST cases treated with oophorectomy or more extensive surgery have followed benign clinical courses. However, 1 of the 3 cases treated with ovarian cystectomy/tumor resection recurred in the residual ovary and iliac fossa 9 years after ovarian cystectomy. Here, we report a case of recurrent MCST in a 38-year-old woman. The patient underwent ovarian cystectomy for a 7.5 cm solid-cystic right ovarian mass, which showed classic morphological and immunophenotypical features of MCST. Four years later, the tumor recurred in the residual right ovary as a 21 cm mass, involving the pelvic peritoneum and omentum. Molecular analysis using next-generation sequencing revealed a single C TNNB1 exon 3 S37A mutation in the recurrent tumor. To the best of our knowledge, this is the second case of recurrent MCST, which presents more evidence that MCST has the potential to recur and spread locally. Rather than ovarian cystectomy/tumor resection, more aggressive surgery, such as unilateral oophorectomy, may be necessary to decrease the risk of recurrence. Long-term postsurgery follow up is needed, especially after simple ovarian cystectomy/tumor resection.

Omental cancer-associated fibroblast-derived exosomes with low microRNA-29c-3p promote ovarian cancer peritoneal metastasis

Ovarian cancer (OC) is characterized by frequent widespread peritoneal metastasis. Cancer-associated fibroblasts (CAFs) represent a critical stromal component of metastatic niche and promote omentum metastasis in OC patients. However, the role of exosomes derived from omental CAFs in metastasis remains unclear. We isolated exosomes from primary omental normal fibroblasts (NFs) and CAFs from OC patients (NF-Exo and CAF-Exo, respectively) and assessed their effect on metastasis. In mice bearing orthotopic OC xenografts, CAF-Exo treatment led to more rapid intraperitoneal tumor dissemination and shorter animal survival. Similar results were observed in mice undergoing intraperitoneal injection of tumor cells. Among the miRNAs downregulated in CAF-Exo, miR-29c-3p in OC tissues was associated with metastasis and survival in patients. Moreover, increasing miR-29c-3p in CAF-Exo significantly weakened the metastasis-promoting effect of CAF-Exo. Based on RNA sequencing, expression assays, and luciferase assays, matrix metalloproteinase 2 (MMP2) was identified as a direct target of miR-29c-3p. These results verify the significant contribution of exosomes from omental CAFs to OC peritoneal metastasis, which could be partially due to the relief of MMP2 expression inhibition mediated by low exosomal miR-29c-3p.

Exosomes from Human Omental Adipose-Derived Mesenchymal Stem Cells Secreted into Ascites Promote Peritoneal Metastasis of Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) patients frequently develop peritoneal metastasis, especially in the human omentum. However, the mechanism underlying this propensity remains unknown. A previous study found that human omental adipose-derived mesenchymal stem cells are potentially involved in ovarian cancer growth and metastasis, but the results were inconsistent and even contradictory. In addition, the underlying mechanisms of visceral adipose metastasis remain poorly understood. Here, our goal is to clarify the role and mechanism of human omental adipose-derived mesenchymal stem cells (HO-ADSCs) in EOC cancer growth and metastasis. We first found that human omental tissue conditioned medium (HO-CM) enhances EOC cell function. Subsequent coculture studies indicated that HO-ADSCs increase the growth, migratory and invasive capabilities of ovarian cancer cells. Then, we demonstrated that exosomes secreted by HO-ADSCs (HO-ADSC exosomes) enhanced ovarian cancer cell function, and further mechanistic studies showed that the FOXM1, Cyclin F, KIF20A, and MAPK signaling pathways were involved in this process. In addition, subcutaneous tumorigenesis and peritoneal metastatic xenograft experiments provided evidence that HO-ADSC exosomes promote ovarian cancer growth and metastasis in vivo. Finally, our clinical studies provided evidence that ascites from ovarian cancer patients enhance EOC cell line proliferation, migration, and invasion in vitro. The present study indicated that HO-ADSC exosomes are secreted into ascites and exert a tumor-promoting effect on EOC growth and metastasis, providing a new perspective and method to develop future novel therapeutic strategies for the treatment of ovarian cancer.

Extrauterine adenomyoma of the lesser omentum: A case report and review of the literature

RATIONALE

The extrauterine adenomyoma is rare and it is extremely rare outside the pelvic cavity. Herein, we reported the first case of a single extrauterine adenomyoma occurring in the lesser omentum.

PATIENTS CONCERNS

This case involved a 55-year-old woman who had undergone subtotal gastrectomy and omentectomy for gastric carcinoma. During postoperational pathological examination, 1 lymph node-like mass was coincidentally found in the lesser omentum. The patient had a history of hysterectomy for uterine leiomyoma 8 years ago.

DIAGNOSES

The resected 17 "lymph nodes" from the lesser omentum were routinely checked for possible metastasis of gastric carcinoma. One of lymph node-like mass was microscopically showed that it was composed of benign smooth muscle components, endometrial glands and stroma by HE staining. Therefore, adenomyoma was initially considered.

INTERVENTIONS

The lymph node-like mass was removed together with the lesser omentum during the subtotal gastrectomy and omentectomy for gastric carcinoma. No special intervention was performed for the adenomyoma.

OUTCOMES

Immunohistochemical staining confirmed that smooth muscle tissue was diffusely and strongly positive for Desmin, smooth muscle actin, estrogen receptor, and progesterone receptor, and negative for CD117, Dog-1, S100, and CD34. Endometrial glands and stroma were positive for estrogen receptor and progesterone receptor, and the endometrium interstitium was also positive for CD10. The final diagnosis of extrauterine adenomyoma occurring in the lesser omentum was established.

LESSONS

So far, to the best of our knowledge, total 53 cases of extrauterine adenomyoma have been reported in 45 English reports. The most common location for a single mass was pelvic cavity (37 cases), but rarely outside the pelvic cavity. This is the first case of a single extrauterine adenomyoma occurring in the lesser omentum.

Omentum: Friend or foe in ovarian cancer immunotherapy?

Ovarian cancer often spreads out of the ovary before a patient is diagnosed and is the deadliest gynecological malignancy. The aggressiveness of ovarian cancer is determined by the progression in the form of peritoneal carcinomatosis, a stage with a poor prognosis and an untreatable condition in most patients. One of the first tumor nests or the origin of metastasis in the peritoneal cavity is the omentum. The omentum contains immune aggregates, called milky spots, embedded in adipose tissue, which support tumor growth by various mechanisms, including immunosuppressive immune cells and metabolic functions. In this sense, the abundance of blood vessels, omental resident macrophages, and chemokines, among other factors, are known to promote invasiveness, proliferation and resistance to cancer therapies. As a result, surgical practice employed in advanced-stage ovarian cancer almost constantly includes omentectomy. Paradoxically, the omentum is considered the "abdominal policeman" that contributes to peritoneal immunity by capturing antigens and pathogens from the peritoneal cavity and promoting effective immune responses against microbes. Why immunosurveillance against the metastatic tumor does not take place in the omentum? Could omental immune responses be activated with immunotherapeutic interventions? The omentum has largely been ignored in cancer immunology and immunotherapy, and the potential translational implications of this in ovarian cancer are still unclear. Here, we focus on the dual role of the omentum in ovarian cancer: its role in antitumor immune responses versus its activities fostering cancer progression.

[Omental infarction, unusual cause of abdominal pain]

INTRODUCTION

Omental infarction describes ischemic torsion of the distal portion of the omentum and constitutes an infrequent cause of acute abdominal pain in childhood of which few cases are known. Objec tive: To analyze through a clinical case the characteristics and management of this pathology, to consider this entity in the differential diagnosis of acute abdominal pain.

CLINICAL CASE

An 11-year- old child consulted the emergency department due to a 48-hour history of continuous abdominal pain, which had progressively increased. On the physical examination, the patient presented pain in the right side of the abdomen and the epigastric area, with no signs of peritoneal irritation, and was overweight (BMI 91st percentile). Biochemical analysis showed a slight increase in c-reactive protein (CRP) 41.31 mg/L (reference value < 3.0 mg/L) without leukocytosis and normal ultrasound study, without visualization of the appendix. Due to persistent pain, increased CRP, and absence of appen dix visualization in the ultrasound, the study was completed with an abdomen and pelvis CT scan which showed trabeculation of the fat of the anterior right subhepatic space, thus diagnosing omental infarction. The patient was hospitalized for conservative management with analgesia, anti-inflamma tory drugs, and fluid therapy, presenting good evolution in the first 48 hours.

CONCLUSION

Omental infarction is an infrequent cause of acute abdominal pain in childhood. Imaging studies play a funda mental role in the differential diagnosis of this entity with other clinical conditions of similar course, thus avoiding unnecessary surgical interventions.

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.

Proteomic Signatures of Human Visceral and Subcutaneous Adipocytes

CONTEXT

Adipose tissue distribution is a key factor influencing metabolic health and risk in obesity-associated comorbidities.

OBJECTIVE

Here we aim to compare the proteomic profiles of mature adipocytes from different depots.

METHODS

Abdominal subcutaneous (SA) and omental visceral adipocytes (VA) were isolated from paired adipose tissue biopsies obtained during bariatric surgery on 19 severely obese women (body mass index > 30 kg/m2) and analyzed using state-of-the-art mass spectrometry. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were performed to investigate proteome signature properties and to examine a possible association of the protein expression with the clinical data.

RESULTS

We identified 3686 protein groups and found 1140 differentially expressed proteins (adj. P value < 0.05), of which 576 proteins were upregulated in SA and 564 in VA samples. We provide a global protein profile of abdominal SA and omental VA, present the most differentially expressed pathways and processes distinguishing SA from VA, and correlate them with clinical and body composition data. We show that SA are significantly more active in processes linked to vesicular transport and secretion, and to increased lipid metabolism activity. Conversely, the expression of proteins involved in the mitochondrial energy metabolism and translational or biosynthetic activity is higher in VA.

CONCLUSION

Our analysis represents a valuable resource of protein expression profiles in abdominal SA and omental VA, highlighting key differences in their role in obesity.

Omental desmoplastic small round cell tumor with metastasis

Desmoplastic small round cell tumor (DSRCT) is a very rare diagnosis with about 200 cases reported in literature. DSRCT is a recently described histopathological entity by Gerald and Rosai in 1989. Abdominopelvic cavity especially peritoneum is the most common site. We report a case of a huge omental DSRCT with lymph node metastasis which was initially misdiagnosed as gastrointestinal stromal tumor on radiology. A 26-year-old male presented with complaints of upper abdominal swelling associated with constant dull pain. On examination there was a large 15 × 12 cm intraabdominal mass in the epigastric and umbilical region. Imaging studies were suggestive of neoplastic mesenchymal etiology. Image-guided fine-needle aspiration cytology (FNAC) was suggestive of mesenchymal neoplastic etiology. On laparotomy, there was a huge 20 × 15 cm mass arising from omentum with multiple omental and mesenteric seedlings and mesenteric, peripancreatic and perigastric lymphadenopathy. The patient underwent debulking surgery with uneventful post-operative recovery. Histopathological examination with immunohistochemistry revealed a diagnosis of DSRCT of omentum and small bowel mesentery with lymph node metastasis. Patient then received adjuvant chemotherapy with multiple chemotherapeutic drugs as per P6 protocol and has stable disease at 1 year follow up.

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.

LYVE1+ macrophages of murine peritoneal mesothelium promote omentum-independent ovarian tumor growth

Two resident macrophage subsets reside in peritoneal fluid. Macrophages also reside within mesothelial membranes lining the peritoneal cavity, but they remain poorly characterized. Here, we identified two macrophage populations (LYVE1hi MHC IIlo-hi CX3CR1gfplo/- and LYVE1lo/- MHC IIhi CX3CR1gfphi subsets) in the mesenteric and parietal mesothelial linings of the peritoneum. These macrophages resembled LYVE1+ macrophages within surface membranes of numerous organs. Fate-mapping approaches and analysis of newborn mice showed that LYVE1hi macrophages predominantly originated from embryonic-derived progenitors and were controlled by CSF1 made by Wt1+ stromal cells. Their gene expression profile closely overlapped with ovarian tumor-associated macrophages previously described in the omentum. Indeed, syngeneic epithelial ovarian tumor growth was strongly reduced following in vivo ablation of LYVE1hi macrophages, including in mice that received omentectomy to dissociate the role from omental macrophages. These data reveal that the peritoneal compartment contains at least four resident macrophage populations and that LYVE1hi mesothelial macrophages drive tumor growth independently of the omentum.

Involvement of ATMIN-DYNLL1-MRN axis in the progression and aggressiveness of serous ovarian cancer

The loss of DYNLL1 contributes to chemoresistance in ovarian cancer. DYNLL1 binds to MRE11, a component of MRN complex (MRE11-RAD50-NBS1), and limits its function in homologous recombination (HR) repair in BRCA1-mutant cells. Decreased activity of MRE11 results in less HR-repair events and thus leads to higher sensitivity against DNA-damaging agents such as cisplatin. Therefore, a better understanding of the cellular changes in DYNLL1-MRN axis in ovarian cancer is needed. Here, we showed that DYNLL1 overexpression leads to decreased chemoresistance even in BRCA-proficient ovarian cancer cells. ATMIN, a transcriptional activator of DYNLL1, showed decreased expression; however, two components of MRN complex, MRE11 and NBS1 (NBN), showed increased expression in high grade compared to low grade serous ovarian cancer. We found that the components of MRN complex (MRE11-RAD50-NBS1) have higher protein levels in sites of omental metastasis and serous tubal intraepithelial carcinoma (STIC) compared to surrounding non-malignant stromal cells in patients with high grade serous ovarian cancer. We showed that the percentage of copy number variation (CNV) events in genes encoding ATMIN, DYNLL1, MRE11 and NBN are the highest in ovarian cancer among other cancer types. ATMIN and DYNLL1 genes are mostly characterized by copy number losses; however, CNV events in MRN complex components are mostly copy number gains. This study highlights the importance of ATMIN-DYNLL1-MRN axis in the development, progression and therapy response of ovarian cancer. MRN levels in ovarian cancer that differ from adjacent, non-malignant tissues may represent actionable therapeutic vulnerabilities.

Matrix lumican endocytosed by immune cells controls receptor ligand trafficking to promote TLR4 and restrict TLR9 in sepsis

Infections and inflammation are profoundly influenced by the extracellular matrix (ECM), but their molecular underpinnings are ill defined. Here, we demonstrate that lumican, an ECM protein normally associated with collagens, is elevated in sepsis patients' blood, while lumican-null mice resolve polymicrobial sepsis poorly, with reduced bacterial clearance and greater body weight loss. Secreted by activated fibroblasts, lumican promotes Toll-like receptor (TLR) 4 response to bacterial lipopolysaccharides (LPS) but restricts nucleic acid-specific TLR9 in macrophages and dendritic cells. The underlying mechanism involves lumican attachment to the common TLR coreceptor CD14 and caveolin 1 (Cav1) in lipid rafts on immune cell surfaces via two epitopes, which may be cryptic in collagen-associated lumican. The Cav1 binding epitope alone is sufficient for cell surface enrichment of Cav1, while both are required for lumican to increase cell surface TLR4, CD14, and proinflammatory cytokines in response to LPS. Endocytosed lumican colocalizes with TLR4 and LPS and promotes endosomal induction of type I interferons. Lumican-null macrophages show elevated TLR9 in signal-permissive endolysosomes and increased response, while wild types show lumican colocalization with CpG DNA but not TLR9, consistent with a ligand sequestering, restrictive role for lumican in TLR9 signaling. In vitro, lumican competes with CD14 to bind CpG DNA; biglycan, a lumican paralog, also binds CpG DNA and suppresses TLR9 response. Thus, lumican and other ECM proteins, synthesized de novo or released from collagen association during ECM remodeling, may be internalized by immune cells to regulate their transcriptional programs and effector responses that may be harnessed in future therapeutics.

Cellular basis of omentum activation and expansion revealed by single-cell RNA sequencing using a parabiosis model

Although the physiological function of the omentum remains elusive, it has been proposed that it plays an important role in fat storage, immune regulation, and regeneration of injured tissues and organs. Although the omentum undergoes expansion upon activation, reports on the accurate assessment of increased cell types and the origin of the increased cells remain limited. To investigate this aspect, the omenta of parabiotic mice were subjected to activation using distinct fluorescent markers and single-cell RNA sequencing (scRNA-seq) was performed to identify circulation-derived omental cells. We found that a considerable number of circulating cells contributed to the activation of the omentum. The omental cells derived from circulating cells exhibited morphological features similar to those of fibroblasts. scRNA-seq revealed the existence of a novel cell population that co-expressed macrophage and fibroblast markers in the activated omentum, suggesting that it corresponded to circulating macrophage-derived fibroblast-like cells. Lineage tracing experiments revealed that most fibroblasts in the activated omentum were not derived from WT1-positive mesenchymal progenitors. The cell cluster also expressed various chemokine genes, indicating its role in the activation and recruitment of immune cells. These results provide important information regarding the activation of the omentum.

Association of Omental Adipocyte Hypertrophy and Fibrosis with Human Obesity and Type 2 Diabetes

OBJECTIVE

Morphological alterations including adipocyte hypertrophy and fibrosis deposition are important surrogate markers of visceral adipose tissue function, but the relationships between these morphological changes and type 2 diabetes mellitus (T2DM) and impaired insulin sensitivity are poorly defined.

METHODS

Omental adipose tissue was obtained from 66 individuals with obesity but without T2DM (OB group), 93 individuals with both obesity and T2DM (T2DM group), and 15 individuals with normal BMI and normal glucose tolerance (NGT group). Adipocyte diameter and volume were measured through pathological section analysis. Pericellular and perilobular fibrosis was determined through picrosirius red staining and immunochemistry, while fibrosis-related genes were tested through gene expression and hydroxyproline content.

RESULTS

Compared with the NGT and OB groups, individuals from the T2DM group displayed increased adipocyte diameter and volume levels. Increased adipocyte size (diameter and volume) was positively associated with hyperglycemia and insulin resistance and inversely correlated with insulin sensitivity (using the Matsuda whole-body insulin sensitivity index assessment of insulin sensitivity) and β-cell function (disposition index 30 and disposition index 120). The fibrosis levels of the OB group were the highest out of the three groups, whereas the fibrosis levels of T2DM individuals were lower than the OB group but higher than the NGT group. Although fibrosis was negatively correlated with T2DM, fibrosis deposition was not remarkably associated with impaired systemic insulin sensitivity and glucose metabolism.

CONCLUSIONS

Compared with fibrosis deposition, adipocyte hypertrophy is more closely associated with T2DM and impaired systemic insulin sensitivity.

Lung cancer combined with diffuse peritoneal and mesenteric amyloidosis detected on 18F-FDG PET/CT: A case report

RATIONALE

Amyloidosis is a heterogeneous group of diseases characterized by extracellular deposition of amyloid fibrils. Lung carcinoma is rarely reported to be associated with AA amyloidosis. With regard to the manifestation of amyloidosis infiltrating organs, most of the cases focus on the heart, liver, kidneys, and peripheral nervous system. Amyloidosis with diffuse abdominal involvement in combination with pulmonary squamous cell carcinoma carcinoma is an exceptionally rare occurrence.

PATIENT CONCERNS

A 70-year-old man was admitted to hospital for a 2-month history of repeated cough, low grade fever, hemoptysis and left back shoulder pain, which was not relieved by nonsteroid anti-inflammatory drugs. Meanwhile, he complained of intermittent diffuse abdominal discomfort and chronic persistent constipation.

DIAGNOSES

The patient was diagnosed with poorly differentiated lung squamous cell carcinoma and diffuse peritoneal and mesenteric amyloidosis based on the pathological biopsy.

INTERVENTIONS

The patient received surgery and chemotherapy for lung tumor. He did not receive any treatment against amyloidosis.

OUTCOMES

The patient died of a severe respiratory infection.

LESSONS

This case indicates that lung carcinoma is suspected to play a causative role in the development of amyloidosis. In addition, amyloidosis should be considered in the differential diagnosis in cases in which diffuse greater omentum, peritoneal, and mesenteric calcifications on 18F-2-fluoro-2-deoxy-D-glucose(18F-FDG) photon emission computed tomography (PET/CT).

Greater-omentum lesion-score (GOLS) as a predictor of residual disease in different regions of the peritoneal cavity in patients undergoing interval cytoreductive surgery for advanced ovarian cancer and its potential clinical utility

BACKGROUND AND AIM

The greater omentum(GO) is a common site of residual disease in patients receiving neoadjuvant chemotherapy for advanced epithelial ovarian cancer. The presence of tumor in the GO could predict presence of disease in other peritoneal regions. The goal of this study was to perform a correlation between the greater-omentum lesion-score(GOLS) and presence of disease in different peritoneal regions and determine its potential utility in guiding interval cytoreductive surgery(CRS).

METHODS

This prospective study included 134 patients undergoing interval CRS from July 1, 2018 to June 30, 2020. Each region of Sugarbaker's Peritobneal Cancer Index(PCI) was given a lesion score(LS) from 0 to 3 according to the diameter of the largest tumor in the region. The GOLS was recorded separately from other structures in the region. Correlation between the GOLS and surgical and pathological LS in each region was performed.

RESULTS

As the GOLS increased, the incidence of disease(surgical LS) in other regions of the peritoneal cavity increased. Receiver operating characteristic(ROC) curves showed area under curve more than 80% for regions 1-2 and 7-8 indicating a high probability of disease in these regions in patients with GOLS 1-3. The positive predictive value(PPV) of preoperative imaging for GOLS was 95.7%. No cut-off of the GOLS could predict presence of disease on pathology with more than 70% accuracy.

CONCLUSIONS

Presence of disease in the GO warrants performing upper abdominal exploration and/or cytoreduction and interval CRS should be planned accordingly in these patients. Imaging has a high PPV in detecting disease in the GO.

Circadian clock dysfunction in human omental fat links obesity to metabolic inflammation

To unravel the pathogenesis of obesity and its complications, we investigate the interplay between circadian clocks and NF-κB pathway in human adipose tissue. The circadian clock function is impaired in omental fat from obese patients. ChIP-seq analyses reveal that the core clock activator, BMAL1 binds to several thousand target genes. NF-κB competes with BMAL1 for transcriptional control of some targets and overall, BMAL1 chromatin binding occurs in close proximity to NF-κB consensus motifs. Obesity relocalizes BMAL1 occupancy genome-wide in human omental fat, thereby altering the transcription of numerous target genes involved in metabolic inflammation and adipose tissue remodeling. Eventually, clock dysfunction appears at early stages of obesity in mice and is corrected, together with impaired metabolism, by NF-κB inhibition. Collectively, our results reveal a relationship between NF-κB and the molecular clock in adipose tissue, which may contribute to obesity-related complications.

Omentectomy Does Not Affect the Postoperative Outcome of Patients With Locally Advanced Gastric Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

To explore the influence of omentectomy on postoperative outcomes in patients with locally advanced gastric cancer (LAGC).

BACKGROUND

Although several meta-analyses have investigated the influence of bursectomy on postoperative outcomes in patients with LAGC, no meta-analyses have explored the influence of omentectomy on postoperative outcomes in such patients.

METHODS

We performed a comprehensive electronic search of the literature up to December 2020 to identify studies that compared postoperative outcomes between patients with LAGC who did and did not undergo omentectomy. A meta-analysis was performed using random-effects models to calculate the risk ratio (RR) and 95% confidence interval (CI), and heterogeneity was analyzed using I² statistics.

RESULTS

Eight retrospective studies involving a total of 2658 patients with LAGC who underwent surgery were included in this meta-analysis. Among them, 3 propensity score matching (PSM) studies demonstrated that the 5-y recurrence-free survival (RFS) rate was 72.9% (314/431) in patients with LAGC who did not undergo omentectomy, whereas it was 70.3% (303/431) in those who did. The results revealed no significant difference in 5-y RFS between groups (RR, 0.91; 95% CI, 0.74-1.13; P = 0.41; I² = 0%). Two PSM studies also revealed no significant difference in 5-y overall survival (OS) between groups (RR, 0.77; 95% CI, 0.52-1.13; P = 0.18; I² = 47%).

CONCLUSIONS

The results of these meta-analyses show that omentectomy had no significant influence on 5-y OS, especially 5-y RFS, in patients with LAGC.

Rapidly Evolving Diffuse Omental Carcinomatosis of Prostate Cancer in 68Ga-PSMA PET/CT

ABSTRACT

An 81-year-old man received androgen deprivation therapy for a locally advanced prostate cancer and, 6 months later, a curative radiation therapy. Half a year later, the patient presented with a steeply increased PSA value (32 ng/mL) and a suppressed testosterone level (0.48 nmol/L). The consecutively performed 68Ga-PSMA PET/CT revealed, besides local tumor remains and several PSMA-positive lymph node and soft tissue metastases, an extensive, diffuse PSMA ligand accumulation in the omentum, which was immunohistochemically proven to be a carcinomatosis of prostate cancer. None of the extraprostatic lesions were present in the pretherapeutic PSMA PET 1 year ago.

Eosinophilic gastroenteritis in an adolescent male with history of chronic bullous disease

Eosinophilic gastroenteritis is a rare inflammatory disorder of the gastrointestinal tract. Although commonly associated with allergic diseases, it is also rarely associated with autoimmune disorders. This case report describes a 17-year-old Filipino male with eosinophilic gastroenteritis, manifesting as abdominal pain, vomiting and diarrhoea. He had no allergic diseases, but he was previously diagnosed with chronic bullous disease. His symptoms improved with the initiation of corticosteroids. To date, this is the first case report of a patient with eosinophilic gastroenteritis and chronic bullous disease.

Abnormal Intestinal Anatomy in Late-stage Human Fetuses: Three Case Series

OBJECTIVE

We reported three cases of fetuses with abnormal intestinal anatomy found during our recent study of the transverse mesocolon using 20 late-stage fetuses.

CASES

The first case (CRL: 328 mm) appeared to have a duodenum and transverse colon trapped in Winslow's foramen (foramen epiploicum) and the duodenum superior portion elongated rightward. The second case (CRL: 264 mm) had a transverse colon inserted deeply into a space between the right kidney and duodenum. The third case (CRL: 276 mm) had a descending colon that ran inferiorly through a deep space between the left kidney and duodenum. Each case had a greater omentum that was shifted leftward, but this is usual. These 3 abnormalities were not evident in the anterior view during dissection of the liver, stomach, jejunum, and ileum. With underdeveloped pancreatic ducts due to unknown reason other than the internal hernia, the first case seemed to be fatal after birth. However, the second and third cases could have recovered after birth because there was no evidence of definite malrotation and because of loose attachments of the intestines to surrounding structures.

CONCLUSIONS

The intestinal morphologies described here could cause some sort of symptoms, such as abdominal pain, whose cause might be difficult to determine.

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.

Greater Omentum Imaging-Reporting and Data System: establishing the grade of benign and malignant lesions of the greater omentum using ultrasonography

OBJECTIVE

To establish Greater Omentum Imaging-Reporting and Data System (GOI-RADS) to evaluate the possibility of omental diseases being malignant.

METHOD

A retrospective analysis was made of 883 patients who had undergone biopsy of the greater omentum in our center from October 2009 to October 2019. Twelve parameters of ultrasonographic images were evaluated, and the odds ratio of each group calculated. We assigned scores for the direct signs (omental echo, omental structure, and omental nodules) and indirect signs (separation of ascites, echo of ascites, mesenteric lymph nodes, and thickening of parietal peritoneum) of omental lesions. We created an omental score (OS) for each patient and receiver operating characteristic (ROC) curve to analyze its effectiveness in the differential diagnosis of benign and malignant omental diseases.

RESULTS

The OS was divided into ≤5, 6, 7, 8, 9, 10, 11, 12, 13, and ≥ 14 points, and the malignant rate was 0, 1.85, 5.56, 30.36, 37.25, 87.72, 96.72, 98.28, 99.08, and 100%, respectively. The area under the ROC curve (AUC) was 0.976. When taking 10 points as the cutoff value to diagnose benign and malignant omental diseases, the sensitivity and specificity was 93.85 and 98.21%, respectively. A grading system was established: grade 1: omental score ≤ 5, malignant rate 0%; grade 2: omental score 6-7, malignant rate ≤ 5.56%; grade 3: omental score 8--9, malignant rate ≤ 37.25%; grade 4: omental score ≥ 10, malignant rate ≥ 87.72.

CONCLUSION

GOI-RADS had high sensitivity and specificity in the differential diagnosis of benign and malignant omental lesions. We believe that GOI-RADS will aid the diagnosis of omental diseases based on objective and accurate interpretation of ultrasound features, and also to promote the ultrasonography of omental diseases in clinical application.

Papillary thyroid carcinoma in Struma Ovarii

Struma Ovarii is one of the types of mature teratoma, with predominant thyroid tissue (>50%). It occurs in 1% of all cases of ovarian tumors and in 2.7% of dermoid tumors. There are no specific clinical, radiological or serum markers for this rare pathology. Rarely it may be accompanied by ascites and the increased level of CA-125. In general Stuma Ovarii is clinically defined as an ovarian malignancy. It is diagnosed only by histopathological examination of the surgical material. Diagnosis of Struma Ovarii dictates the need for advanced research of the thyroid. Struma Ovarii is mostly benign. Its malignant transformation occurs in only 5% of all cases, That leads to further management planning analogous to the treatment of thyroid cancer. The case of malignant Struma Ovarii of the 50-year-old woman, which led to total thyroidectomy and radioactive iodine therapy - is described.

Schwannoma in the hepatoduodenal ligament with portal vein invasion: A case report

RATIONALE

Schwannomas are mesenchymal tumors with low malignant potential that originate from Schwann cells. They can occur in most parts of the body, such as the head, neck, and extremities. Schwannoma in the hepatoduodenal ligament is extremely rare, and only four cases have been reported in the literature.

PATIENT CONCERNS

Herein, we describe a 58-year-old female who presented with right epigastric pain for 10 days. Preoperative computed tomographic (CT) revealed a 4.5 cm × 3.8 cm tumor in the hepatic hilar area.

DIAGNOSES

Schwannoma in the hepatoduodenal ligament with portal vein invasion.

INTERVENTIONS

Intraoperative findings revealed that the tumor was identified in the hepatoduodenal ligament, and the left branch of the portal vein was compressed. Complete tumor resection with reparation of the portal vein was performed for the patient. Postoperative pathological examination confirmed the final diagnosis of benign schwannoma, characterized by abundant spindle-shaped cells and positive reactivity for S-100 protein.

OUTCOMES

The patient had a good prognosis and had no recurrence after 37 months of follow-up.

LESSONS

Our case of schwannoma in the hepatoduodenal ligament is unique owing to the portal vein invasion, aimed at helping recognize the difficulty of preoperative diagnosis.

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.

[Protruding omentum with umbilical fluid leakage in a patient with liver cirrhosis]

A 57 year old woman with a history of liver cirrhosis and ascites presented with serous exudate spontaneously leaking from a ruptured umbilical hernia, also known as Flood syndrome. This syndrome is a rare complication of decompensated liver cirrhosis and is associated with high mortality. In this specific case, there was also omentum protruding through the umbilical hernia which limited the outflow of ascites. Patient was successfully treated with antibiotics and consecutive open primary hernia repair without mesh implantation.

Type-5 abomasal ulcer and omental bursitis in 14 cows

BACKGROUND

Type-5 abomasal ulcer (U5) is a perforated ulcer that causes peritonitis limited to the omental bursa. This retrospective study describes the clinical and laboratory findings in 14 cattle with omental bursitis due to U5. The medical records of 14 cows aged 2.5 to 14.6 years (5.4 ± 3.1 years) with U5 were scrutinised.

RESULTS

The most common clinical findings were partial or complete anorexia (100%), abdominal guarding (100%), obtunded demeanour (93%), congested scleral vessels (79%), tachypnoea (71%), rumen atony (64%), diminished faecal output (64%), reduced skin surface temperature (64%) and fever (46%). Four (29%) cows had between one and four concomitant diseases. The most common abnormal laboratory findings were hypokalemia (71%), haemoconcentration (57%), metabolic acidosis (57%) and azotaemia (43%). All cows were euthanased; five immediately after the initial examination, one after exploratory laparotomy and eight after unsuccessful treatment. A diagnosis of U5 was made in all cows during postmortem examination.

CONCLUSIONS

There is a need for improvement of the antemortem diagnosis of U5 because reliable differentiation of this disease from other conditions with a similar clinical presentation is currently not feasible.

Capillary hemangioma arising from the lesser omentum in an adult: A case report

RATIONALE

Although capillary hemangiomas, common lesions involving the proliferation of small capillary vessels and a single layer of endothelial cells, can arise in any organ, they are rarely reported in the greater or lesser omentum. Here in, we report a case of capillary hemangioma arising from the lesser omentum in an adult with interesting diagnostic imaging findings, including changes in tumor size over time on computed tomography (CT), that was resected using laparoscopic surgery. To our knowledge, this is the first English report to describe a capillary hemangioma arising from the lesser omentum.

PATIENT CONCERNS

A 63-year-old Japanese man received hemodialysis for chronic renal failure due to diabetic nephropathy, and a small, gradually enlarging tissue mass was found near the lesser curvature of the stomach on plain CT performed annually, without any associated complaints. Diagnostic imaging revealed an 18 × 15-mm tumor with a homogenous, highly enhanced effect in the early phase that was attenuated but prolonged in the delayed phase. Magnetic resonance imaging showed a mass with low signal intensity on T1-weighted imaging and relatively high signal intensity on T2-weighted imaging.

DIAGNOSIS

The patient was diagnosed with capillary hemangioma arising from the lesser omentum according to the pathological and immunohistological findings.

INTERVENTIONS

The patient underwent laparoscopy for excision of the tumor from the lesser omentum.

OUTCOMES

At the 1 year follow-up, the patient had no recurrence of the tumor.

LESSONS

We describe the first case worldwide of capillary hemangioma that was a true vascular tumor arising from the lesser omentum. Although capillary hemangioma arising from the lesser omentum is extremely rare, it should be considered in the differential diagnosis of patients presenting with a highly enhanced lesser omental tumor, and laparoscopy can be safely applied for the excision of this tumor.

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.

Laparoscopic resection of abdominal cystic lymphangioma derived from lesser omentum: Case report

RATIONALE

Cystic lymphangiomas are uncommon congenital malformations that originate from lymphatic channels. Lymphangiomas frequently appear in the head, neck, and axillary regions of children. Abdominal cystic lymphangiomas are extremely rare, having a reported incidence of 1 in 20,000 to 250,000.

PATIENT CONCERNS

A 50-year-old female patient was admitted to our hospital with a cough that had persisted for several weeks. Abdominal ultrasonography incidentally revealed a multilocular cystic lesion in the lesser curvature of the stomach.

DIAGNOSIS

Preoperative findings indicated that the lesion was cystic lymphangioma. However, the possibility of a pancreatic tumor could not be completely excluded.

INTERVENTIONS

Laparoscopy revealed a multilocular cyst in the lesser curvature of the stomach. The gastrocolic ligament was divided, and the body and tail of the pancreas was exposed in the omental bursa, showing that the cystic lesion was not derived from the pancreas but from the lesser omentum. Although it was located directly beside the left gastric artery, the cyst was enucleated and totally resected laparoscopically without sacrificing the artery.

OUTCOMES

The cystic lesion was histopathologically diagnosed as an abdominal cystic lymphangioma originating from the lesser omentum. The patient was discharged on the postoperative day 4 without complications.

LESSONS

Preoperative imaging cannot completely distinguish abdominal cystic lymphangiomas from other types of cystic tumors. Because cystic lymphangiomas have the potential to grow, invade vital structures, and develop life-threatening complications, laparoscopic assessment followed by total resection is considered a useful treatment strategy for peripancreatic cystic lesions.

Endodermal Sinus Tumor of the Omentum: Case Report

We report a case of primary endodermal sinus tumor of the omentum in a 46-year-old woman. The patient had been referred to our hospital for pain in the right abdomen. CT scan revealed a right-sided abdominal mass. At laparotomy, a large omental tumor extending to the bowel, uterus, ovaries and peritoneum was found, and it was totally resected. The tumor displayed the typical histological patterns observed in endodermal sinus tumor, and the immunohistochemical findings confirmed the diagnosis. Serum AFP level was 21.550 ng/ml prior to laparotomy, and decreased to 13.845 ng/mL after surgery, whereas the level of serum beta human chorionic gonadotropin was normal. Post-surgery, the patient received combination chemotherapy consisting of cisplatin, etoposide and bleomycin every 3 weeks for a total of 6 cycles. At the end of the treatment, all the findings, including AFP level, were normal.

Effects of hypothyroidism on the mesenteric and omental adipose tissue in rats

To characterize the influence of hypothyroidism on the endocrine activity of mesenteric and omental adipose tissue (MOAT) and the peripheral regulation of energy balance (EB) in rats, we analyzed food intake (FI); basal metabolic rate (BMR); locomotor activity; body weight (BW); serum hormone concentrations and the expression of their receptors in MOAT. We evaluated the morphology and differentiation of adipocytes. Hypothyroidism decreased FI, BMR and BW. The percentage of visceral white adipose tissue (WAT) depots and the morphology of adipocytes were similar to euthyroid rats. Serum leptin and adiponectin expression in MOAT were altered by hypothyroidism. The expression of Perilipin 1, HSL, UCP1 and PRDM16 was significantly lower in MOAT of hypothyroid animals. Hypothyroidism in rats leads to a compensated EB by inducing a white adipocyte dysfunction and a decrease in BW, BMR, FI and adipokine secretions without changing the percentage of WAT depots and the morphology of the MOAT.

A 35 Year Old Bangladeshi Lady with Hereditary Mucinous Ovarian Cancer, Complicated with Omental Metastasis

Approximately 80% ovarian tumors are benign, and these arise mostly in young adult females. Malignant tumors are more prevalent in ageing women, between the ages of 45-65 years. Mucinous ovarian cancer represents about 5% of epithelial ovarian cancers (EOC). We have reported a case of mucinous cystadenocarcinoma in 35-year-old lady with metastasis to momentum. Imaging (Radiograph & CT scan) studies showed a large right sided pelvic mass with probable origin in the right ovary. Cancer antigen-125 was elevated, while carcinoembrionic antigen and alpha-fetoprotein were normal. Mutational profiles shown distinct finding, as KRAS mutations positive nevertheless p53 and BRCA mutations are absent. She had undergone total abdominal hysterectomy with bilateral salphingo-oopherectomy along with pelvic dissection for removal of lymph nodes at the age of 35. She was given 3 cycles of chemotherapy with cisplatin and paclitaxel. To the best of our knowledge, this is the one of the little cases of ovarian mucinous cystadenocarcinoma being reported at a relatively young age and the first case being reported from Bangladesh.

Report: Laparoscopic management for coexistent parasitic ovarian teratoma of the omentum and ovarian mucinous cystadenoma: A case report

We report a case of a 34-year-old woman who underwent laparoscopy for her adnexal tumor. Coexistence of ovarian mucinous cystadenoma and parasitic ovarian teratoma of the omentum was found and successfully treated by laparoscopic surgery. As our case presented, it is thought that the omental teratomas could be resulting from the auto-amputation and re-implantation of a dermoid cyst of the ovary.

TOTAL OMENTECTOMY IN GASTRIC CANCER SURGERY: IS IT ALWAYS NECESSARY?

BACKGROUND

Traditionally, total omentectomy is performed along with gastric resection and extended lymphadenectomy in gastric cancer (GC) surgery. However, solid evidences regarding its oncologic benefit is still scarce.

AIM

To evaluate the incidence of metastatic omental lymph nodes (LN) in patients undergoing curative gastrectomy for GC, as well as its risk factors and patients' outcomes.

METHODS

All consecutive patients submitted to D2/modified D2 gastrectomy due to gastric adenocarcinoma from March 2009 to April 2016 were retrospectively reviewed from a prospective collected database.

RESULTS

Of 284 patients included, five (1.8%) patients had metastatic omental LN (one: pT3N3bM0; two: pT4aN3bM0; one: pT4aN2M0 and one pT4bN3bM0). Four of them deceased and one was under palliative chemotherapy due relapse. LN metastases in the greater omentum significantly correlated with tumor's size (p=0.018), N stage (p<0.001), clinical stage (p=0.022), venous invasion growth (p=0.003), recurrence (p=0.006), site of recurrence (peritoneum: p=0.008; liver: p=0.023; ovary: p=0.035) and death (p=0.008).

CONCLUSION

The incidence of metastatic omental LN of patients undergoing radical gastrectomy due to GC is extremely low. Total omentectomy may be avoided in tumors smaller than 5.25 cm and T1/T2 tumors. However, the presence of lymph node metastases in the greater omentum is associated with recurrence in the peritoneum, liver, ovary and death.

Low proliferative potential of adipose-derived stromal cells associates with hypertrophy and inflammation in subcutaneous and omental adipose tissue of patients with type 2 diabetes mellitus

BACKGROUND

Obesity and type 2 diabetes mellitus (T2DM) are among the most important morbidity factors. In this study we tested the hypothesis that low proliferative potential of adipose derived stromal cells (ADSC) associates with reduced formation of new fat depots, excess accumulation of fat in the functional adipocytes and their hypertrophy, resulting in fat inflammation and insulin resistance.

METHODS

We screened two groups of obese patients with or without T2DM, matched for BMI, age, and duration of obesity to test the hypothesis that hypertrophy and decreased renewal of adipocytes may underlie transition from obesity to T2DM. All patients were matched for carbohydrate metabolism (fasting blood glucose level, glycated hemoglobin, HOMA-IR index and M-index). The subcutaneous and omental fat tissue biopsies were obtained during bariatric surgery from obese individuals with or without T2DM. The morphology and immunophenotype of subcutaneous and omental fat was assessed in frozen tissue sections. ADSC were isolated from both types of fat tissue biopsies and screened for morphology, proliferative potential and inflammatory status.

RESULTS

The non-diabetic patients had normal carbohydrate metabolism and moderate insulin resistance measured by HOMA-IR and hyperinsulinemic clamp (M-index), while T2DM patients were extremely insulin resistant by both indexes. The average size of diabetic adipocytes was higher than that of non-diabetic in both subcutaneous and omental fat tissues, indicating adipocyte hypertrophy in T2DM. Both these tissues contained higher level of macrophage infiltration and increased M1-like to M2-like ratio of macrophage subpopulations, suggesting increased fat inflammation in T2DM. This was confirmed by increased activatory phosphorylation of stress-induced JNK1/2 in diabetic ADSC.

CONCLUSION

These results suggest that blunted proliferation and increased hypertrophy of diabetic ADSC may lead to reduced insulin sensitivity via increased inflammation mediated by M1 macrophages and JNK1/2 pathway.

[A Case of Giant GIST Originating from the Greater Omentum]

A 60-year-old woman was admitted for abdominal distention, abdominal pain, and anorexia. Abdominal CT showed a 30×20 cm mass with contrast effect. gastrointestinal stromal tumor(GIST) of the omentum or the mesenterium was suspected. Peritoneal nodules were also recognized. We performed palliative surgery. The tumor was considered to have originatedfrom the greater omentum andinvolvedthe marginal artery of the transverse colon. We performedpartial excision of the transverse colon andresection of the tumor. Immunohistochemically, the tumor cells were c-kit(+), CD34(+), S100(-), andDOG1(-), with 1 fission image for 50 fields of view with high magnification. The patient was diagnosed with high-risk GIST originating from the greater omentum. The patient was started on imatinib administration on the 37th day but died on the 109th day.