Mesenteric Castleman Disease Mimicking Neuroendocrine Tumor.

Castleman disease (CD) is a benign lymphoproliferative disorder of unknown etiology, which can involve any part of the body. CD can involve a single lymph node (unicentric) or multiple lymph nodes (multicentric) of which unicentric CD is the most common type. The unicentric CD is usually localized, asymptomatic, and often appears as an incidental mass on radiographs, whereas multicentric CD is characterized by systemic involvement. Mesenteric involvement of CD is very rare. In this article, we present a case of the unicentric CD of small bowel mesentery, which mimicked a neuroendocrine tumor preoperatively.

Mesenteric Mixed Type of Castleman Disease: A Report of a Rare Case.

Castleman disease is a rare type of lymph node hyperplasia primarily affecting the mediastinum, with mesenteric localization being extremely uncommon. It is classified into solitary and multicentric forms. In this case report, we present the case of a 46-year-old female patient in whom an incidental mesenteric mass was discovered during the workup for a ventral hernia. The mass was completely excised, and the histopathological examination confirmed the diagnosis of mixed-type Castleman disease. Surgery is the treatment of choice for localized forms of this condition, and histological examination is crucial in confirming the diagnosis.

Long-Term Survival Outcomes After Minimally Invasive Surgery for Ileal Neuroendocrine Tumors.

BACKGROUND: Ileal neuroendocrine tumors (i-NETs) are characterized by their multifocality and bulky mesenteric mass. Having shown that minimally invasive surgery (MIS) utilizing a hand-access port device has favorable short-term outcomes and achieves the goals of surgery for i-NETs, we sought to analyze long-term survival outcomes of MIS. METHODS: One hundred and sixty-eight patients who underwent resection of primary i-NETs at a single institution between January 2007 and February 2023 were retrospectively studied. Patients were categorized into the MIS or open surgery cohorts on an intention-to-treat basis. Open surgery was selected mainly based on the need for hepatectomy or bulky mesenteric mass resection. Overall survival was analyzed using log-rank tests with propensity score matching (PSM) and Cox proportional hazards regression. PSM was performed to reduce standardized mean differences of the variables to <0.2. RESULTS: Overall, 129 (77%) patients underwent MIS and 39 (23%) underwent open surgery. Twenty-seven MIS patients were converted to an open procedure. The median follow-up time was 49 months (interquartile range 23-87 months). In the PSM cohorts, overall survival did not differ significantly between the MIS and open surgery cohorts {median 99 months (95% confidence interval [CI] 91-not applicable [NA]) vs. 103 months (95% CI 86-NA), p = 0.77; hazard ratio 0.87 (95% CI 0.33-2.2), p = 0.77}. CONCLUSIONS: MIS is an alternative to open surgery for i-NETs, achieving similar short- and long-term oncological outcomes. Bulky mesenteric mass and a plan for concurrent liver resection are potential criteria for open surgery.

Adult Mesenteric Lymphangioma Resulting in Small Bowel Obstruction.

A mesenteric cystic lymphangioma (MCL) is a rare condition that primarily manifests in children. This case report illustrates an unusual presentation of an MCL causing a small bowel obstruction with volvulus in an adult. We present a 31-year-old male who presented to our hospital with a small bowel obstruction. He underwent laparotomy, and a lymphatic mass acting as a lead point and causing small bowel volvulus was discovered intra-operatively. The patient underwent a small bowel with associated mass resection and primary anastomosis; he recovered well. The final pathology demonstrated an MCL. Despite the MCL being a rare entity in adults, it must be considered as the differential for various abdominal pathologies. Although the majority of these masses lack malignant potential, they should be resected, as they pose a risk of mechanical obstruction, torsion, and perforation. Prior descriptions include individual case reports of symptomatic lesions, proposed non-operative management, and follow-up imaging.

Outcome on Mesenteric Mass Response of Small-Intestinal Neuroendocrine Tumors Treated by 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy: The MesenLuth Study, a National Study from the French Group of Endocrine Tumors and Endocan-RENATEN Network.

A mesenteric mass (MM), characterized by fibrotic reaction, is present in most small-intestinal neuroendocrine tumors (SI-NETs). 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) has shown its efficacy in patients with progressive SI-NETs. However, because of specific tissue characteristics of desmoplastic MMs, we hypothesize that these lesions may be refractory to 177Lu-DOTATATE PRRT. Methods: From the national French Groupe d'étude des Tumeurs Endocrines database, we identified patients with an advanced SI-NET and a MM (≥2 cm with a retractile aspect) of a SI-NET treated by at least 1 course of 177Lu-DOTATATE PRRT. The primary endpoint was a MM objective response rate (ORR) of less than 5%. Secondary endpoints were metabolic response, MM-related safety, and clinical response, as well as MM progression-free survival (PFS) and non-MM PFS. Results: In total, 52 patients were included. The MM ORR was 4% (n = 2), and the non-MM ORR was 8% (n = 4). No patient had a MM metabolic response, and the non-MM metabolic response rate was 12% (n = 6). Among the 26 patients with baseline MM-related symptoms, 46% had a clinical response. Four patients presented with gastrointestinal complications during PRRT. The median MM-related PFS was not reached, and the non-MM PFS was 50.3 mo (95% CI, 38.2-61.7 mo). Conclusion: This study confirms that 177Lu-DOTATATE PRRT does not lead to morphologic response on MMs (ORR < 5%). However, it allows MM stability, with few MM-related side effects, and has a relevant impact on MM-related symptoms.

Clinicopathological findings, treatment, and outcome in 60 cats with gastrointestinal eosinophilic sclerosing fibroplasia.

BACKGROUND: Gastrointestinal eosinophilic sclerosing fibroplasia (GESF) in cats presents as mass(es) associated with the gastrointestinal tract, mesentery, and abdominal lymph nodes. HYPOTHESIS/OBJECTIVES: To report the clinicopathological findings, treatment, and outcome of cats with GESF. ANIMALS: Sixty client-owned cats diagnosed with GESF. METHODS: Retrospective review of medical records of cats with histopathologically confirmed GESF. RESULTS: The median age was 5.4 years (interquartile range [IQR], 3.3-8.9.); 30% were Domestic Shorthairs and 12% were Domestic Longhair cats, with the most prevalent pedigree breeds being Ragdolls (25%), Exotic Shorthair (10%) and Persian (8%) cats. The median duration of clinical signs was 90 days (IQR, 17.5-247.0); the most common clinical signs were weight loss (60%), hyporexia/anorexia (55%), chronic vomiting (37%), lethargy (35%) and chronic diarrhea (27%). Masses were located in the small intestine (32%), stomach (27%), ileocolic junction (15%), colon (10%), lymph node (8%) and mesentery (8%) and 15% of cats had >1 mass. Eosinophilia was present in 50% and hypoalbuminemia in 28% of cats. The mass was removed surgically in 37% of cases. Most cats (98%) were treated with corticosteroids. Survival was not statistically different between cats treated with surgical resection and cats treated with medical therapy alone, 88% of the cats were still alive at the time of writing. CONCLUSIONS AND CLINICAL IMPORTANCE: GESF is an important differential diagnosis for abdominal masses in cats, and has a much better prognosis than previously reported.

Cracking the Code of a Rare Colonic Mesentery Gastrointestinal Neuroendocrine Tumor Disguised as Chronic Gastroenteritis: The Critical Art of Timely Detection.

Neuroendocrine tumors (NETs) typically present in the setting of metastasis from other solid organs and are considered late manifestations of the disease. Therefore, primary tumors are extremely rare. NETs of the colonic mesentery occur more than 70% of the time in the appendix, small intestine, and rectum. Here, we describe the case of a patient who presented with multiple episodes of diarrhea and abdominal pain, which was waxing and waning in occurrence, with CT findings of a rare primary NET.

An accidental finding of a retroperitoneal desmoid tumor: case report and review of the literature.

Retroperitoneal desmoid-type fibromatosis is a rare benign mesenchymal neoplasm that develops as a result of fibroblastic proliferation within the musculoaponeurotic stroma. The authors present the case of a 41-year-old male patient who was referred for a retroperitoneal neoplasm. A mesenteric mass core biopsy was done, and it revealed a low-grade spindle cell lesion consistent with desmoid fibromatosis.

An Isolated Mesenteric Presentation of a Nodal Peripheral T Cell Lymphoma with T Follicular Helper Cell Phenotype.

Nodal peripheral T cell lymphoma (PTCL) with T follicular helper (TFH) cell phenotype is a provisional entity added to the 2016 revised WHO classification of haematological malignancies. These lymphomas have an aggressive clinical course and respond poorly to conventional treatments. Distinct histological features have not been well described. Additionally, the minimum criteria for diagnosis is not well established but detection of at least two TFH markers in addition to CD4 is suggested to assign a TFH cell phenotype. Some pathological features of angioimmunoblastic T cell lymphoma (AITL) such as recurrent molecular alterations are commonly found. As the name suggests, these lymphomas are nodal in origin with patients presenting with widespread lymphadenopathy. We describe the first documented case of nodal PTCL with a TFH phenotype presenting as an isolated mesenteric mass with no nodal involvement.

Diagnostic Performance of Point Shear Wave Elastography (pSWE) Using Acoustic Radiation Force Impulse (ARFI) Technology in Mesenteric Masses: A Feasibility Study.

PURPOSE: To evaluate the diagnostic performance of ultrasound point shear wave elastography (pSWE) using acoustic radiation force impulse (ARFI) technology in different benign and malignant mesenteric masses (MMs). METHODS: A total of 69 patients with MMs diagnosed from September 2018 to November 2021 were included retrospectively in the study. The inclusion criteria were (1) an MM over 1 cm; (2) valid ARFI measurements; and (3) confirmation of the diagnosis of an MM by histological examination and/or clinical and radiological follow-up. To examine the mean ARFI velocities (MAVs) for potential cut-off values between benign and malignant MMs, a receiver operating characteristics analysis was implemented. RESULTS: In total, 37/69 of the MMs were benign (53.6%) and 32/69 malignant (46.4%). Benign MMs demonstrated significantly lower MAVs than mMMs (1.59 ± 0.93 vs. 2.76 ± 1.01 m/s; p < 0.001). Selecting 2.05 m/s as a cut-off value yielded a sensitivity and specificity of 75.0% and 70.3%, respectively, in diagnosing malignant MMs (area under the curve = 0.802, 95% confidence interval 0.699-0.904). CONCLUSION: ARFI elastography may represent an additional non-invasive tool for differentiating benign from malignant MMs. However, to validate the results of this study, further prospective randomized studies are required.

Small Intestinal Neuroendocrine Neoplasm: Factors Associated with the Development of Local Tumor-Related Symptoms.

INTRODUCTION: Clinical presentations of small intestinal neuroendocrine neoplasms (SiNENs) can range from asymptomatic to life-threatening complications. Other than primary tumor(s), mesenteric mass (MM) can provide local tumor-related (LTR) symptoms. Although some expert centers propose routine primary resection to avoid complications in stage IV patients, some guidelines suggest avoiding primary tumor resection unless in the presence of symptoms. This study was aimed to identify factors associated with the presence or development of LTR symptoms. METHODS: From 2012 to 2019, SiNEN patients with appropriate initial morphological imaging were included. All initial imaging was reviewed. Associations between factors and LTR symptoms were assessed by logistic regression. RESULTS: Among 144 SiNEN patients, 66 met the inclusion criteria. Multivariate analysis identified on initial morphological imaging (i) any visible primary tumor (p < 0.01) and (ii) MM contact ≥180° with the superior mesenteric vessels (p ≤ 0.02), as independent factors associated with LTR symptoms in the whole study population as well as in the subgroup of primary resected patients. Among the 14 (21%) patients with both factors on initial cross-sectional conventional imaging, 12 (18%) were straightaway symptomatic at diagnosis and the remaining became symptomatic during the follow-up. All asymptomatic patients, without upfront surgery and without any predictive factor 16/18 (89%), stayed asymptomatic during the 2.7-year median follow-up. The absence of association between these 2 factors yielded a sensitivity of 100%, a specificity of 62%, and a negative predictive value of 100% for the occurrence of LTR symptoms. CONCLUSION: The presence of any visible primary tumor and/or MM superior mesenteric vessels contact ≥180° at initial cross-sectional imaging are 2 easily identifiable factors, which can help physicians for the decision-making regarding timing and type of surgery for SiNENs. Larger multicenter studies should endorse these results.

Idiopathic Sclerosing Mesenteritis: An Extremely Rare Cause of Mesenteric Mass.

Idiopathic sclerosing mesenteritis (ISM) is an extremely rare condition in which mesenteric adipose tissue undergoes necrotic and fibrotic changes. It is also known as "retractile mesenteritis", "mesenteric panniculitis" or "fat necrosis of the mesentery". Most cases are seen in Caucasian males between the fifth and seventh decades of life. Some of the suggested causes of this extremely rare condition include autoimmune disorders, abdominal trauma, malignancy, abdominal infections and even IgG4-related diseases; however, the actual cause remains unknown. Most cases are either self-limiting or improve with medical therapy. However, aggressive cases requiring emergent surgical interventions to relieve intestinal obstruction have been reported in the literature. We present a case of a 60-year-old male patient who presented to the emergency room with severe abdominal pain and was diagnosed with ISM that required surgical intervention to relieve the symptoms.

Massive Abdominal Distension in a Five-Year-Old Child: Management of a Giant Mesenteric Cyst.

Mesenteric cyst is a rare entity with a very low incidence. The majority of the cases are incidental. Despite several theories, its etiology remains unknown. Some cases present with non-specific symptoms such as pain abdomen, swelling, and abdominal mass. It may rarely get complicated due to hemorrhage, torsion, or rupture of the cyst. Large mesenteric cysts are quite uncommon. However, these cysts seldom grow to produce clinical symptoms arising from compression of adjoining structures, such as vomiting, constipation due to intestinal obstruction, or dyspnoea due to compression of the diaphragm. Despite several theories, its etiology remains unknown. Diagnosis can be achieved with the help of radiological examinations such as ultrasonography (USG), contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), and confirmed by histopathological examination. We report a case of a giant mesenteric cyst in a five-year-old girl.

Sclerosing Mesenteritis, a Rare Cause of Mesenteric Mass in a Young Adult: A Case Report.

Sclerosing mesenteritis (SM) is a rare fibroinflammatory disorder that involves mesenteric adipose tissue, more frequently localized in the small intestine, with an insidious clinical presentation having symptoms related to mass effect, usually resulting in bowel obstruction, mesenteric ischemia, as well as rapid weight loss. We report a case of a 23-year-old male presenting with palpable abdominal mass, mesogastric pain, and a history of rapid weight loss, who underwent exploratory laparoscopy. A hemorrhagic and gelatinous nodular tumor mass of the mesentery was identified and the surgical procedure was converted to a laparotomic approach. Histologically, the mass was composed of a proliferation of bland-looking spindle cells with slightly eosinophilic cytoplasm and elongated normochromatic nuclei with mild nuclear atypia, haphazardly set in a collagenized stroma; fat necrosis and inflammatory cells (lymphocytes, plasma-cells, and histiocytes) were also evident. The diagnosis of sclerosing mesenteritis was made. Our case emphasizes that histology remains pre-eminent for a correct diagnosis of SM, as pre-operative radiological-based diagnosis is non-specific.

Predicting symptomatic mesenteric mass in small intestinal neuroendocrine tumors using radiomics.

Metastatic mesenteric masses of small intestinal neuroendocrine tumors (SI-NETs) are known to often cause intestinal complications. The aim of this study was to identify patients at risk to develop these complications based on routinely acquired CT scans using a standardized set of clinical criteria and radiomics. Retrospectively, CT scans of SI-NET patients with a mesenteric mass were included and systematically evaluated by five clinicians. For the radiomics approach, 1128 features were extracted from segmentations of the mesenteric mass and mesentery, after which radiomics models were created using a combination of machine learning approaches. The performances were compared to a multidisciplinary tumor board (MTB). The dataset included 68 patients (32 asymptomatic, 36 symptomatic). The clinicians had AUCs between 0.62 and 0.85 and showed poor agreement. The best radiomics model had a mean AUC of 0.77. The MTB had a sensitivity of 0.64 and specificity of 0.68. We conclude that systematic clinical evaluation of SI-NETs to predict intestinal complications had a similar performance than an expert MTB, but poor inter-observer agreement. Radiomics showed a similar performance and is objective, and thus is a promising tool to correctly identify these patients. However, further validation is needed before the transition to clinical practice.

Surgical Excision of Sclerosing Mesenteritis, Exploration of an Unknown Mesenteric Mass.

Sclerosing mesenteritis is a rare and often benign condition characterized as a fibrotic disease consisting of non-suppurative inflammation of adipose tissue. Through mass effect, sclerosing mesenteritis can compromise the gastrointestinal lumen as well as mesenteric vessel integrity. There is a poor understanding of this disorder and its pathogenesis, which presents with various symptomatology and often without identification of inciting factors. Patients with sclerosing mesenteritis exhibit gastrointestinal and systemic manifestations including weight loss, fever, nausea, vomiting, diarrhea, and abdominal pain. This case presents a patient with a seven-month history of chronic, epigastric abdominal pain following laparoscopic surgery for acute uncomplicated appendicitis. The patient underwent work-up with computed tomography and magnetic resonance enterography that confirmed the presence of a mesenteric mass of unknown etiology located in the mid-epigastrium. Due to the inability to safely sample the mass, the patient underwent diagnostic laparoscopy, which was subsequently converted to an open procedure where excision of the mesenteric lesion was performed. Surgical pathology revealed fat necrosis with fibrosis, granulomatous inflammation, and dystrophic calcifications consistent with sclerosing mesenteritis. The patient was seen in follow-up with the resolution of her epigastric abdominal pain. This case report demonstrates a unique presentation of a symptomatic patient with a mesenteric mass not amenable to non-invasive biopsy. Complete excision of this lesser sac mass revealed sclerosis mesenteritis as the pathological cause.

Desmoplastic mesenteric lesions do not respond radiographically to peptide receptor radionuclide therapy.

177 Lu-Dotatate treatment is indicated for progressive, well-differentiated, small bowel neuroendocrine tumours) NETs. These tumours often metastasise to mesenteric lymph nodes and produce a desmoplastic reaction, consisting of tumour cells interspersed with fibrotic tissue. We hypothesised that, in patients treated with 177 Lu-Dotatate, mesenteric tumours would remain stable even as liver tumour size changes were observed. We retrospectively reviewed the records of all patients treated with 177 Lu-Dotatate between April 2018 and December 2019. Among patients with desmoplastic mesenteric tumours and liver metastases, we evaluated changes in tumour size of mesenteric and liver lesions based on pre- and post-treatment anatomic scans. As a result of the infrequency of objective radiographic response, any reported changes in tumour size were considered significant. Twenty-one patients met the inclusion criteria: nine had evidence of shrinkage of liver lesion(s), one had mild progression of liver lesions, seven had stable hepatic disease and four had a mixed hepatic response. Two of the patients with hepatic tumour shrinkage met the criteria for a partial response via RECIST 1.1 (https://recist.eortc.org). Desmoplastic mesenteric lesions remained unchanged in size, regardless of the changes detected in liver lesions. In conclusion, 177 Lu-Dotatate does not impact desmoplastic mesenteric tumours which are typically associated with midgut NETs. Patients whose disease is predominantly confined to desmoplastic mesenteric lesions are unlikely to respond radiographically to peptide receptor radionuclide therapy. Moreover, the inclusion of desmoplastic mesenteric lesions as target lesions in RECIST measurements tends to increase rates of disease stability vs response or progression.

Surgical Principles in the Management of Small Bowel Neuroendocrine Tumors.

OPINION STATEMENT: Small bowel neuroendocrine tumors (SB NETs) are increasing in frequency and becoming more common in surgical practice. It is often difficult to make the diagnosis of a SB NET at an early stage, as the primary tumor tends to be small and patients are asymptomatic until there is regional or distant metastasis, when they develop abdominal pain, partial obstruction, or bleeding and/or develop carcinoid syndrome. Despite this advanced presentation at the time of diagnosis, patients with metastatic SB NETs, as compared to other gastrointestinal malignancies, have favorable survival, which can be improved by appropriate surgical interventions. With the lack of randomized studies, there is reasonable controversy surrounding the optimal management of patients with SB NETs. As such, treatment of these patients is driven primarily by physician experience and available data based predominantly on retrospective studies. Based on this, current recommendations advocate for patients with SB NETs (localized or metastatic) to be managed at experienced centers by a multidisciplinary team. Eligible patients should undergo surgical resection of primary and regional disease as outlined in this article. Additionally, patients with metastatic disease should be evaluated on a case by case basis to evaluate surgical options that may mitigate bowel symptoms (i.e., pain, intestinal angina, obstruction) and carcinoid symptoms (flushing, diarrhea, hemodynamic instability) and prolong survival. Unlike other gastrointestinal malignancies, aggressive surgical management of these patients, even in the context of unresectable metastatic disease, can improve patients' symptoms and long-term survival. The principles outlined in this article are geared to guide appropriate management of SB NET patients with improvement in quality of life and overall survival outcomes.

Awareness of a mesenteric mass as a common manifestation of ileal neuroendocrine tumor.

Omori et al. reported a case of multiple liver metastases originating from synchronous double cancer of "primary mesenteric neuroendocrine tumor" and rectal cancer. However, the "primary mesenteric neuroendocrine tumor" might be a misrecognition of mesenteric metastasis from ileal neuroendocrine tumor. Ileal neuroendocrine tumor is extremely rare in Japan. Herein, we aim to describe the characteristics of ileal neuroendocrine tumor and mesenteric mass as its common manifestation in reference to their reported case.