A clinician's perspective on the new organ mesentery and non-vascular mesenteropathies.

Mesentery was discovered as a new organ in 2017. It is a continuous membranous tissue from the duodenojejunal flexure to the anorectal junction. It has distinct anatomy, physiology, and disease states. Primary mesenteropathies include vascular and non-vascular diseases. Some of them are common, and some of them are rarely seen in clinical practice. Secondary mesenteropathies occur when infection or malignancy in another organ spreads to the mesentery. Each entity has specific diagnostic and treatment protocols. Increased awareness of different mesenteropathies and an understanding of their various presentations at different stages of life can help in early diagnosis and improved clinical outcomes.

Mesenteric inflammatory pseudotumor: A rare case report and review of the literature.

Inflammatory pseudotumor (IP) is a rare type of benign tumor. Although initially identified in the lung, it has now been identified in a number of somatic and visceral sites, but mesenteric presentation is uncommon and has a variable clinical presentation. As inflammatory pseudotumor mimic malignancy both clinically and radiologically, the radiologist should be familiar with this entity. The only effective treatment is complete surgical resection. We present the case of a 55-year-old woman who presented with chronic abdominal pain and was diagnosed with a mesenteric inflammatory pseudotumor, in an attempt to illustrate the different imaging aspects of this benign condition in ultrasound, computed tomography and magnetic resonance imaging, and to simplify the description of these tumors.

Intraabdominal mature cystic teratoma in a 20-year-old male: A rare case.

Teratomas are the most prevalent type of germ cell tumors and usually display benign characteristics. Mature cystic teratomas consist of a varied mixture of mature tissue types that originate from squamous epithelium and skin adnexal structures. It is most commonly found in female gonads. A mature teratoma located in the abdomen of an adult male patient is exceptionally uncommon. In this case, we report a rare case of intra-abdominal mature cystic teratoma in an adult male.

Unexpected diagnosis of rare mesenteric Castleman disease: A case report and literature review.

In this report, we present an Asian male patient who was 30 years old and admitted to the hospital due to pancreatitis. While undergoing a CT scan, an isolated mass was unexpectedly discovered in the patient's abdomen. The patient's abdominal pain, which was caused by pancreatitis, had resolved before he underwent surgical resection to remove the mass. Subsequently, the patient was diagnosed with Castleman disease based on pathology. Castleman disease occurring in the mesentery is exceptionally rare. Therefore, we have reviewed the essential information regarding Castleman disease and have found that the crucial part lies in the diagnosis and the consideration of distinct treatment strategies based on different types.

Heterotopic mesenteric ossification caused by trauma: A case report.

BACKGROUND: Heterotopic mesenteric ossification (HMO) is a clinically rare condition characterized by the formation of bone tissue in the mesentery. The worldwide reporting of such cases is limited to just over 70 instances in the medical literature. The etiology of HMO remains unclear, but the disease is possibly induced by mechanical trauma, ischemia, or intra-left lower quadrant abdominal infection, leading to the differentiation of mesenchymal stem cells into osteoblasts. Here, we present a rare case of HMO that occurred in a 34-year-old male, who presented with left lower quadrant abdominal pain. CASE SUMMARY: We report the case of a 34-year-old male patient who presented with left lower abdominal pain following trauma to the left lower abdomen. He subsequently underwent surgical treatment, and the postoperative pathological diagnosis was HMO. CONCLUSION: We believe that although there is limited literature and research on HMO, when patients with a history of trauma or surgery to the left lower abdomen present with corresponding imaging findings, clinicians should be vigilant in distinguishing this condition and promptly selecting appropriate diagnostic and therapeutic interventions.

MSCs-exosomes can promote macrophage M2 polarization via exosomal miR-21-5p through Mesenteric injection: a promising way to attenuate murine colitis.

BACKGROUND AND AIMS: Exosome-based therapies are gaining increasing attention, with growing evidence suggesting a link between alterations in mesentery adipose tissue (MAT) and intestinal disease in Crohn's disease (CD). However, the specific mechanism by which mesenchymal stem cells (MSCs)-Exos may alleviate colitis through targeting MAT remains not fully understood. METHODS: Human umbilical cord MSCs (HucMSCs) were cultured to isolate the corresponding exosomes (HucMSCs-Exos), which were confirmed by their morphology, size distribution, and expression of markers. In vivo, 2,4,6-trinitrobenzenesulfonic acid solution (TNBS) and dextran sodium sulfate (DSS) -induced mouse colitis models were used to detect the therapeutic effects of HucMSCs-Exos. ELISA, qRT-PCR, western blotting, and immunofluorescence determined the expression of key molecules. Luciferase reporter assay was used to confirm the relationship between miR-21-5p and SPRY2. RESULTS: Exosomes treatment through mesenteric injection demonstrated therapeutic effects on mesenteric inflammation and colitis. These therapeutic benefits were contingent on macrophages, significantly facilitating the M2 polarization of mesenteric macrophages. The expression data from GSE159814 and GSE211008 revealed that exosomal miR-21-5p was enriched in HucMSCs-Exos and could be delivered to macrophages. Additionally, the results indicated that miR-21-5p could directly target the 3'UTR of SPRY2 and activate the phosphorylation of ERK to modify macrophage phenotypes. Mechanistically, exosomal miR-21-5p derived from HucMSCs could promote macrophage M2 polarization via the SPRY2/ERK axis. CONCLUSION: Mesenteric injection of HucMSCs-Exos significantly alleviates mesenteric inflammation and colitis by promoting mesenteric macrophage M2 polarization, making it a promising approach to treat colitis and suggesting therapeutic potential role of exosomal miR-21-5p in CD.

Mesenteric Panniculitis.

Background: Mesenteric panniculitis (MP) is an uncommon non-neoplastic idiopathic inflammation of adipose tissue, mainly affecting the mesentery of the small intestine, with its etiology remaining largely speculative. The difference in prevalence of MP among females and males varies across multiple studies. In most cases, MP is asymptomatic; however, patients can present with nonspecific abdominal symptoms or can mimic underlying gastrointestinal and abdominal diseases. The diagnosis is suggested by computed tomography and is usually confirmed by surgical biopsies if necessary. Treatment is generally supportive and based on a few selected drugs, namely, nonsteroidal anti-inflammatory drugs or corticosteroids. Surgery is reserved when the diagnosis is unclear, when malignancy is suspected or in the case of severe presentation such as mass effect, bowel obstruction, or ischemic changes. Summary: MP is a rare inflammatory condition of the mesentery often asymptomatic but can cause nonspecific abdominal symptoms. Diagnosis relies on computed tomography imaging, with treatment mainly supportive, utilizing medications like nonsteroidal anti-inflammatory drugs or corticosteroids, while surgery is reserved for severe cases or diagnostic uncertainty. Key Messages: MP causes abdominal pain, and it is mainly diagnosed with CT scan.

Navigating the labyrinth of peritoneal and extraperitoneal anatomy: abdominal spread made easy with a case based review.

Essential to understanding disease spread in abdomen is to separate the peritoneum from the extraperitoneum. These areas have distinct anatomy with well-define separate pathways. The peritoneum is comprised of connected recesses that are potential spaces, normally not imaged except when containing excess fluid or air. Peritoneal recesses are formed by the opposing peritoneal surfaces and subdivided by the attachments of the ligaments and mesenteries to the parietal peritoneum. Disease flows within the recesses by changes in abdominal pressure. This forms a distinct spread pattern. The extraperitoneum is traditionally stratified by the renal fascia into the anterior and posterior pararenal spaces and the perirenal space. The fascia contains and directs spread from the contained organs with the compartments. Each space has a unique spread pattern defined by the containing fascia. The extraperitoneum is connected to the mesenteries and ligaments forming the subperitoneal space. This space interconnects the extraperitoneum with the mesenteries allowing for the normal continuum of blood vessels, lymphatics, and nerves but also forms the pathways for bidirectional spread of disease.

Pseudomixoma peritoneal: reporte de un caso / Peritoneal Pseudomyxoma: A Case Report

Resumen El pseudomixoma peritoneal (PMP) es una afección poco común, inicialmente descrita en 1884 por Werth en relación con la ascitis y tumores mucinosos de ovario, y posteriormente en 1901 por Frankel, asociado a tumores mucinosos apendiculares. Se ha observado una alta prevalencia de mutaciones en el gen K-RAS y TP53 en pacientes con PMP de bajo grado, lo que desencadena la proliferación y producción excesiva de moco. Los estudios han demostrado que la cavidad peritoneal, especialmente la superficie hepática, es el sitio principal de depósito de estos tumores. La tomografía computada se considera el estándar de oro para el diagnóstico, mientras que la resonancia magnética es más sensible para detectar el origen tumoral y evaluar la extensión de la enfermedad. Aunque la laparotomía exploratoria es el método tradicional para la toma de biopsias, se están explorando alternativas menos invasivas como la biopsia guiada por ultrasonido y tomografía computarizada, que han demostrado ser eficaces. El diagnóstico diferencial incluye la endometriosis y tumores mixoides, con énfasis en la invasión al mesenterio y las características quísticas. Es crucial reconocer las diferencias en etapas avanzadas, ya que el PMP tiende a invadir los órganos desde afuera, mientras que los tumores mixoides presentan metástasis sólidas a distancia.

Abstract Pseudomyxoma peritonei (PMP) is a rare condition, first described by Werth in 1884 in association with ascites and ovarian mucinous tumors, and later in 1901 by Frankel, associated with appendicular mucinous tumors. High prevalence of mutations in the K-RAS and TP53 genes has been observed in patients with low-grade PMP, triggering proliferation and excessive mucus production. Studies have shown that the peritoneal cavity, especially the hepatic surface, is the main site for deposition of these tumors. Computed tomography is considered the gold standard for diagnosis, while magnetic resonance imaging is more sensitive for detecting the tumor origin and assessing disease extent. Although exploratory laparotomy is the traditional method for biopsy, less invasive alternatives such as ultrasound-guided and computed tomography-guided biopsy are being explored, which have proven to be effective. The differential diagnosis includes endometriosis and mixoid tumors, with emphasis on mesentery invasion and cystic characteristics. Recognizing differences in advanced stages is crucial, as PMP tends to invade organs from the outside, while mixoid tumors present distant solid metastases.

Mesentery lymphangioma led to the acute abdomen, a case report with a rare location and unexpected diagnosis.

INTRODUCTION: Lymphangioma is a benign tumor, containing thin-walled lymphatic spaces. The most affected sites are head, neck, axilla, and parenchymal organs. Mesentery lymphangioma is a rare case; it happens in <1 % of cases. PRESENTATION OF CASE: A 25-year-old man came to the hospital, complaining of acute abdominal pain. The pain started in the morning and developed progressively. The physical examination was not helpful. The abdominal X-ray in the erect position was within normal. The ultrasound imaging findings were limited; they showed only a cystic mass in the pelvis. So, the investigatory laparotomy was indicated. During the laparotomy, we found a sizeable mass originating from the small bowel mesentery and pressed on it. The mass is located at a distance of 50 cm from the treitz ligament. We excised the mass and related intestinal loops. The histopathological examination showed that it was a cystic lymphangioma. DISCUSSION: Lymphangioma is a benign tumor that forms when early lymphatic spaces fail to connect to the lymphatic system. The diagnosis of the lesion depends on radiological investigations because the manifestations and the laboratory investigations are not specific, but histopathology examination is still the only method to determine diagnosis. The treatment of lymphangioma depends on radical surgery. CONCLUSION: Mesenteric lymphangioma is a rare condition with unspecific symptoms and radiological and laboratory findings, so we should keep it in mind when the patient comes with general abdominal manifestations and we cannot put a determined diagnosis. Laparotomy should be done rapidly in such cases to avoid life-threatening complications.

A ruptured mesenteric lymphangioma causing peritonitis: a case report.

Cystic lymphangioma is a rare disease that is mainly diagnosed in childhood. When diagnosed, the lesion presents an indication for surgery due to the risk of serious complications. Herein, we report the case of a 32-year-old patient who presented to the emergency room for abdominal pain that developed 2 days before with worsening symptoms and abdominal pain in the last 24 hr. The computed tomography showed diffuse wall thickening of the jejunum and proximal ileum with mesenteric fat infiltration, a mesenteric collection, and a moderate volume of ascites extending into the pelvis. A laparotomy was performed, revealing diffuse chemical peritonitis with a crater-like lesion in the jejunal mesentery, secreting lymphatic fluid. The mesenteric lesion was then excised, and the histological examination showed a ruptured cystic lymphangioma. Lymphangiomas of the small bowel mesentery are rare and may be exceptionally associated with bowel occlusion or peritonitis.

A Novel Ex Vivo Tumor Spheroid-Tissue Model for Investigating Microvascular Remodeling and Lymphatic Blood Vessel Plasticity.

Biomimetic tumor microenvironment models bridge the gap between in vitro and in vivo systems and serve as a useful way to address the modeling challenge of how to recreate the cell and system complexity associated with real tissues. Our laboratory has developed an ex vivo rat mesentery culture model, which allows for simultaneous investigation of blood and lymphatic microvascular network remodeling in an intact tissue environment. Given that angiogenesis and lymphangiogenesis are key contributors to the progression of cancer, the objective of this study was to combine tissue and tumor spheroid culture methods to establish a novel ex vivo tumor spheroid-tissue model by verifying its use for evaluating the effects of cancer cell behavior on the local microvascular environment. H1299 or A549 tumor spheroids were formed via hanging drop culture and seeded onto rat mesenteric tissues harvested from adult male Wistar rats. Tissues with transplanted spheroids were cultured in serum-free media for 3 to 5 days. PECAM, NG2, CD11b, and αSMA labeling identified endothelial cells, pericytes, immune cells, and smooth muscle cells, respectively. Time-lapse imaging confirmed cancer cell type specific migration. In addition to increasing PECAM positive capillary sprouting and LYVE-1 positive endothelial cell extensions indicative of lymphangiogenesis, tumor spheroid presence induced the formation of lymphatic/blood vessel connections and the formation of hybrid, mosaic vessels that were characterized by discontinuous LYVE-1 labeling. The results support the application of a novel tumor spheroid microenvironment model for investigating cancer cell-microvascular interactions.

Case report: Rapidly progressive desmoid tumor after surgery for esophagogastric junction cancer and slowly progressive primary desmoid tumor: a report of two cases and literature review.

Background: Desmoid tumor (DT) is a rare locally aggressive but non-metastatic mesenchymal soft tissue neoplasm that predominantly occurs in the abdominal wall, abdominal cavity, and extremities. Its occurrence in the mesentery is relatively uncommon. Case reports: This article reports two cases of desmoid tumor treated at the Department of Gastrointestinal Surgery, Weifang People's Hospital. The first case was a 59-year-old male patient who had previously undergone surgery for esophagogastric junction cancer. Postoperatively, he developed an intra-abdominal mass that rapidly increased in size within three months. The second case was a 60-year-old male patient who incidentally discovered a mass in the left lower abdomen. Both patients underwent surgical treatment, and the postoperative pathological diagnosis was mesenteric desmoid tumor. Conclusion: The treatment of desmoid tumor remains challenging. Simple surgical resection often yields unsatisfactory outcomes, and the efficacy of adjuvant radiotherapy and chemotherapy is also limited. Further research and clinical practice are necessary to improve diagnostic and therapeutic strategies, aiming to enhance patient survival and quality of life.

The mesenteric entry site as a potential weak point in gastrointestinal anastomoses - findings from an ex-vivo biomechanical analysis.

PURPOSE: Gastrointestinal disorders frequently necessitate surgery involving intestinal resection and anastomosis formation, potentially leading to severe complications like anastomotic leakage (AL) which is associated with increased morbidity, mortality, and adverse oncologic outcomes. While extensive research has explored the biology of anastomotic healing, there is limited understanding of the biomechanical properties of gastrointestinal anastomoses, which was aimed to be unraveled in this study. METHODS: An ex-vivo model was developed for the biomechanical analysis of 32 handsewn porcine end-to-end anastomoses, using interrupted and continuous suture techniques subjected to different flow models. While multiple cameras captured different angles of the anastomosis, comprehensive data recording of pressure, time, and temperature was performed simultaneously. Special focus was laid on monitoring time, location and pressure of anastomotic leakage (LP) and bursting pressures (BP) depending on suture techniques and flow models. RESULTS: Significant differences in LP, BP, and time intervals were observed based on the flow model but not on the suture techniques applied. Interestingly, anastomoses at the insertion site of the mesentery exhibited significantly higher rates of leakage and bursting compared to other sections of the anastomosis. CONCLUSION: The developed ex-vivo model facilitated comparable, reproducible, and user-independent biomechanical analyses. Assessing biomechanical properties of anastomoses offers an advantage in identifying technical weak points to refine surgical techniques, potentially reducing complications like AL. The results indicate that mesenteric insertion serves as a potential weak spot for AL, warranting further investigations and refinements in surgical techniques to optimize outcomes in this critical area of anastomotic procedures.

Total small bowel volvulus on incomplete common mesentery, an exceptional complication in geriatric patients: A rare case report.

INTRODUCTION AND IMPORTANCE: The incomplete common mesentery, resulting from a rotational anomaly, is a rare but potentially life-threatening condition. This congenital anomaly is characterized by persistent embryonic bowel arrangement and an extremely short mesentery root. Complications typically manifest during neonatal or pediatric stages, with limited occurrences in adulthood. Herein, a compelling case of an 83-year-old male with small bowel volvulus and incomplete common mesentery, underscoring the critical importance of recognizing and addressing rare but potentially life-threatening complications in the geriatric population. CASE PRESENTATION: An 83-year-old male, post-prostatectomy, presented with acute abdominal distress, indicating small bowel volvulus associated with incomplete common mesentery. Dehydration signs were evident on admission, and imaging confirmed the diagnosis. Urgent surgical intervention, including the Ladd procedure, successfully resolved the condition with a six-day recovery. CLINICAL DISCUSSION: Fetal digestive tract rotation anomalies lead to incomplete common mesentery, posing risks of volvulus. Complications, whether acute or chronic, require timely recognition. Diagnostic modalities, including the "whirlpool" sign on imaging, play a vital role. The Ladd procedure remains the standard treatment, addressing mesenteric anomalies and preventing recurrence. CONCLUSION: This case highlights the critical nature of small bowel volvulus with incomplete common mesentery, emphasizing the importance of recognizing and managing this rare condition promptly. Awareness, diagnostic accuracy, and timely surgical intervention are crucial for favorable outcomes, particularly in the geriatric population.

Cecal volvulus in complete common mesentery.

Common mesentery is an abnormal rotation of the primary umbilical loop characterized by inverted positioning of the mesenteric vessels; the mesenteric vein is displaced to the left of the artery. The inversion can be complete or incomplete. If it is incomplete, the mesenteric root is very short, with an empty right iliac fossa and the caecum in high median or subhepatic position. If it is complete, the entire small intestine is on the right, the entire large intestine is on the left; there is no third duodenum, and the second duodenum is anastomosed in the jejunum to the right of the superior mesenteric vessels. Cecal volvulus is a rarely encountered cause of acute intestinal occlusion and should be considered as a surgical emergency. There exist two main types of volvulus: by twisting of the large intestine around its axis, which remains in place; or by tilt and to rotation of the colon, which changes position.

A case of significant loss of mesenteric fat: Educational and clinical relevance.

Mesenteric fat, a type of intraperitoneal adipose tissue, plays a critical role in protection and the immune response. Loss of mesenteric fat is a known consequence of a variety of clinical conditions; however, visual documentation of this rare occurrence is not available in the literature searched. Here we report a case of significant loss of mesenteric fat identified during educational dissection of a 79-year-old male fresh frozen donor cadaver, causing the mesenteric folds to appear transparent. The gross anatomical characteristics, clinical importance, and educational significance of this abnormality are described in this report. Knowledge of this condition may be of interest to clinicians, and documentation could benefit anatomists and educators dissecting and teaching in the laboratory setting.

Mesenteric root pseudocyst: finding in an asymptomatic patient-a case report.

BACKGROUND: Mesenteric cysts are one of the rarest abdominal tumor masses, representing a little-studied pathology. In turn, the variability and non-specificity of clinical manifestations make diagnosis difficult, as it can be reached by imaging findings due to another cause or by non-specific abdominal pain. CASE PRESENTATION: This article describes the case report of an asymptomatic 28-year-old patient who presented a 6-cm abdominal cystic mass with mixed density, which was found incidentally by computed tomography. Exploratory laparoscopy was performed followed by conversion to conventional surgery to extract the tumor mass. The anatomical pathology diagnosis was pseudocyst of the mesentery root. Mesenteric cysts are one of the rarest abdominal tumor masses, representing a little-studied pathology. In turn, the variability and non-specificity of clinical manifestations make diagnosis difficult, as it can be reached by imaging findings due to another cause or by non-specific abdominal pain. CONCLUSIONS: Mesenteric cysts are rare, and their nonspecific symptoms often lead to diagnosis based on imaging findings. Complete laparoscopic enucleation is the standard treatment.

Idiopathic Isolated Mesenteric Panniculitis: A Case Report of a Rare Adipose Tissue Disease.

Mesenteric panniculitis belongs to a spectrum of rare diseases affecting the fatty tissue of the mesentery. It is characterized by chronic inflammation and fibrosis of the mesenteric adipose tissue of the bowel. Patients typically present with symptoms such as abdominal pain, nausea, vomiting, anorexia, bloating, and weight loss. Computed tomography (CT) is commonly used for diagnosis in most cases. We present a case of a 42-year-old male who experienced a significant escalation of abdominal pain over a 24-hour period. Despite seeking medical care at multiple hospitals and being prescribed analgesics, his pain remained unrelieved. Based on CT findings and the worsening pain, mesenteric panniculitis was suspected, leading to a diagnostic laparoscopy that confirmed the diagnosis. The patient was treated for idiopathic isolated mesenteric panniculitis during his hospital stay and was subsequently discharged. This article emphasizes the importance of considering mesenteric panniculitis as a possible differential diagnosis in patients with nonspecific abdominal pain, to avoid overlooking this condition.