Primary mesenteric carcinoid tumor

Unveiling the rarity: A case report of giant peritoneal loose body

Peritoneal loose bodies, also referred to as peritoneal mice, are formed by torsion of epiploic appendages detaching from the large bowel, subsequently becoming loose within the peritoneal cavity. While often discovered incidentally during laparotomy or autopsy, emerging reports suggest they can manifest with diverse symptoms. Here, we present a 61-year-old patient experiencing lower abdominal pain and irritative voiding symptoms, ultimately diagnosed with a giant peritoneal loose body measuring 6.5 cm. Computed tomography (CT) imaging showed a well-circumscribed soft-tissue density mass with central calcifications, which was later confirmed during surgery. Only a few cases have been reported on giant peritoneal loose bodies. We also highlight characteristic features of imaging to establish the correct diagnosis.

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.

Well-differentiated gastro-entero-pancreatic neuroendocrine tumors with positive FDG-PET/CT: a retrospective chart review

PURPOSE

Rarely, well-differentiated gastro-entero-pancreatic neuroendocrine tumors (GEP NETs) can have positive uptake on 18F-fluorodeoxyglucose-PET/computerized tomography ( 18 F-FDG-PET/CT), with or without a positive 68 Ga-PET/CT. We aim to evaluate the diagnostic role of 18 F-FDG-PET/CT in patients with well-differentiated GEP NETs.

METHODS

We retrospectively reviewed a chart of patients diagnosed with GEP NETs between 2014 and 2021, at the American University of Beirut Medical Center, who have low (G1; Ki-67 ≤2) or intermediate (G2; and Ki-67 >2-≤20) well-differentiated tumors with positive findings on FDG-PET/CT. The primary endpoint is progression-free survival (PFS) compared to historical control, and the secondary outcome is to describe their clinical outcome.

RESULTS

In total 8 out of 36 patients with G1 or G2 GEP NET met the inclusion criteria for this study. The median age was 60 years (range 51-75 years) and 75% were male. One patient (12.5%) had a G1 tumor whereas 7 (87.5%) had G2, and seven patients were stage IV. The primary tumor was intestinal in 62.5% of the patients and pancreatic in 37.5%. Seven patients had both 18 F-FDG-PET/CT and 68 Ga-PET/CT positive and one patient had a positive 18 F-FDG-PET/CT and negative 68 Ga-PET/CT. Median and mean PFS in patients positive for both 68 Ga-PET/CT and 18 F-FDG-PET/CT were 49.71 months and 37.5 months (95% CI, 20.7-54.3), respectively. PFS in these patients is lower than that reported in the literature for G1/G2 NETs with positive 68 Ga-PET/CT and negative FDG-PET/CT (37.5 vs. 71 months; P  = 0.0217).

CONCLUSION

A new prognostic score that includes 18 F-FDG-PET/CT in G1/G2 GEP NETs could identify more aggressive tumors.

Primary grade 2 neuroendocrine tumor of the ileal mesentery: a case report

Background

The prevalence and incidence of neuroendocrine tumors (NETs) are increasing worldwide. Primary mesenteric NETs are extremely rare. Solid tumors that arise in the mesentery are typically metastatic. We present an extremely rare case of a primary grade 2 NET (NET G2) in the ileal mesentery.

Case presentation

A 54-year-old man was referred to our hospital for further examination of a previously diagnosed right mesenteric tumor. Mild tenderness was noted on the right side of the abdomen, but there were no palpable masses. Fluorodeoxyglucose-positron emission tomography (FDG-PET) revealed slight FDG uptake (maximum standardized uptake value, 2.0) in the right abdomen, and a benign or low-grade malignant tumor was suspected. We extracted the ileal mesenteric tumor with an ileal resection (90 cm). The cut surface of the 55 × 33 × 33 mm³ tumor was pale yellowish-white. Immunohistochemistry revealed diffuse staining for synaptophysin and chromogranin A, and focal staining for CD56. The Ki-67 index was 3%. The final pathological diagnosis was NET G2. The patient’s postoperative course was uneventful, and he developed no recurrence 1.5 years after surgery. Postoperative antitumor therapy was not performed for this patient because the histological diagnosis was NET G2, and it was determined that the tumor could be completely resected by surgery.

Conclusions

We report an extremely rare case of primary ileal mesenteric NET. Mesenteric tumors that show slight FDG uptake on FDG-PET examination should be considered well-differentiated NET.

An apparent primitive mass of the mesentery: A case report

INTRODUCTION

Neuroendocrine tumours (NETs) are rare tumors. 55% of NETs originate in the gastrointestinal tract and the liver is the most common site of distant metastases. Serum chromogranin A is the most common biomarker for assessing the extent of disease and monitoring treatment; carcinoid syndrome occurs in 19% of NETs and is characterized by chronic diarrhea or flushing. Primary mesenteric NETs are rare and have been described only in case reports in literature; our case is an apparent primary mesenteric NETs with a surgical program to remove the mesenteric mass and subrenal interaortocaval and retrocaval lymphadenectomies.

PATIENT CONCERNS

A 73-year old man came to us because he had been experiencing abdominal pain for a year and he had recently developed diabetes mellitus. He was an active smoker with arterial hypertension.

DIAGNOSIS

After a computed tomography scan and 68 Gallium-positron emission tomography, a diagnosis of what appeared to be a primary mesenteric NET with retrocaval and interaortocaval lymph nodes was made. Laparoscopic biopsy showed NET G2 positive for serotonin, chromogranin A, synaptophysin.

INTERVENTIONS

The intraoperative finding of a primitive ileum-NET changed the surgical program. We removed the mesenteric mass with the lymph nodes of the superior mesenteric vessel and the middle distal ileum along with the cecum.

OUTCOMES

The postoperative course was normal, and the patient was discharged on the seventh postoperative day without signs of short bowel syndrome. Follow-up at 6 months revealed no evidence of short bowel syndrome or disease progression.

CONCLUSION

68 Gallium-positron emission tomography does not show NETs smaller than 0.5 mm. Accurate palpation of the intestine is essential during surgery for NETs for two reasons: to find the primitive, and because of the risk of multiple intestinal primitives.

Immunoglobulin G4-related systemic disease: mesenteric and peritoneal involvement with radiopathological correlation and differential diagnoses

Since its first introduction in 2003 by Kamisawa et al., IgG4-related disease has gained wide interest in the imaging community, and several manuscripts have been published regarding its imaging features. In addition to initial observations in the pancreaticobiliary system, it is now well known that the disease may involve every organ system in the body. There is not much information in the imaging literature about the involvement of mesentery, omentum, and peritoneum in this disease. This article aims to provide more information about the imaging findings of IgG4-related disease regarding these areas by making radiopathological correlations and discussing the possible differential diagnoses.

Primary versus secondary nature of mesenteric neuroendocrine tumours

Neuroendocrine tumours (NETs) are rare group of malignancy that originate from neuroendocrine cells present throughout the body. Most patients with NET first present with symptoms associated with metastasis, and up to 20% of patients have unknown primary site of tumour. Most common metastatic sites for small intestine NETs (SI-NETs) are the locoregional lymph nodes and liver. Although mesenteric metastasis through direct extension or lymphatic spread from SI-NETs is common, mesenteric extranodal involvement is extremely rare, and its biology and primary versus secondary nature are not well understood. Due to their small size and location, SI-NETs are frequently undetected on anatomical imaging or indium-111-pentetreotide single-photon emission computed tomography/CT (Octreoscan) and are difficult to be found via endoscopy. Gallium-68-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-octreotate positron emission tomography (⁶⁸Ga-DOTATATE PET)/CT has been increasingly used for accurate staging, unknown primary tumour site localisation and appropriate management planning. We present a case of an incidentally found mesenteric NET with occult SI-NETs localised preoperatively by ⁶⁸Ga-DOTATATE PET/CT.

Multiple liver metastases originating from synchronous double cancer of neuroendocrine tumor and rectal cancer: a case report

Background

Neuroendocrine tumor (NET) is a relatively rare tumor and can develop in almost any organ, but primary mesenteric NETs are extremely rare. In addition, liver metastases from synchronous double cancer of neuroendocrine tumor graded as G1 and second primary malignancies (SPMs) have never been reported before. We herein report a case of multiple liver metastases from synchronous double cancer of NET (G1) at the ileal mesentery and rectal cancer.

Case presentation

A 66-year-old man was identified as having tumors in the rectum and the ileal mesentery by computed tomography (CT). He underwent laparoscopic low anterior resection for rectal cancer and biopsy of the ileal mesentery lymph node and was diagnosed with rectal cancer as pT3 pN1 cM0 (stage IIIB) and NET (G1) of the ileal mesentery. He received oxaliplatin and capecitabine (XELOX) for 3 months as adjuvant chemotherapy for rectal cancer. The NET (G1) of the ileal mesentery was low grade and had not expanded at follow-up. A CT scan performed 4 years after the surgery indicated multiple liver metastases. All the metastases had the same findings on CT and magnetic resonance imaging (MRI). Thus, the patient underwent the first stage of modified associating liver partition and portal vein ligation for staged hepatectomy (modified ALPPS), comprising partial hepatectomies of segments 3 and 4, ligation of the right branch of portal vein, and hepatic partition on the demarcation line, followed by the second stage of modified ALPPS (right lobectomy). Histopathological findings revealed that the 14 nodules were metastatic liver tumors of rectal cancer and the 2 nodules were liver metastases of the NET (G1).

Conclusions

Our findings suggest that synchronous double cancer of NET and gastrointestinal cancer may be indistinguishable in preoperative images. However, curative resection, precise pathological diagnosis, and adequately adjusted treatment may result in a better prognosis.

Primary mesenteric neuroendocrine tumour with liver metastasis: a common presentation of an uncommon tumour

Neuroendocrine tumours (NET) are rare. They usually arise from the gastrointestinal or bronchopulmonary systems. Most are discovered incidentally and the small bowel tumours pose special difficulty in detection and treatment. Primary mesenteric involvement is very rare. Here we report such a case with a liver metastasis. This was preoperatively diagnosed and treated by enucleation of the mesenteric tumour together with right hepatectomy in a single sitting.

Radiological and histological findings of an asymptomatic ever-increasing neoplasm: The small bowel neuroendocrine tumor (NET)

The small bowel neuroendocrine tumor is a rare but ever-increasing tumor, most of the time asymptomatic and found incidentally. An early diagnosis can consistently change the prognosis.

Primary Mesenteric Carcinoid Tumor Presenting with Carcinoid Syndrome

Neuroendocrine neoplasms (NENs) are a diverse group of tumors arising throughout the body with a common origin from neuroendocrine cells. Well-differentiated NENs, also known as neuroendocrine tumors (NETs), are generally indolent and are often found incidentally, while poorly differentiated tumors are more aggressive. Carcinoid tumors are NETs arising from the gastrointestinal tract and less commonly from the lungs, thymus, and kidneys. NETs in the mesentery arise from metastasis from primary tumor, and carcinoid syndrome in this setting results from concomitant metastasis to the liver. Primary mesenteric carcinoid tumors are very rare. We present a 64-year-old man with carcinoid syndrome from a mesenteric carcinoid tumor without evidence of liver metastasis or other primary tumor sites.

Multimodality Imaging Findings in Carcinoid Tumors: A Head-to-Toe Spectrum

Carcinoid tumors are a rare biologically heterogeneous group of neuroendocrine tumors with a spectrum ranging from benign indolent to aggressive metastatic tumors. They belong to the category of amine precursor uptake and decarboxylase tumors, or apudomas. The most common sites for primary locations are the gastrointestinal and respiratory tracts; however, any organ can be involved. The clinical presentation depends on location, aggressiveness, production of biologically active amines and peptides, paraneoplastic syndromes, and tendency for metastasis. Their reported age-adjusted incidence has increased in recent years, partly due to improved detection at radiologic imaging and endoscopy. Not a ll neuroendocrine cell tumors are carcinoids. Numerous systems have been proposed regarding their nomenclature and classification. Cross-sectional and functional imaging plays an important role in diagnosis, lesion characterization, and staging. Awareness of nomenclature, classification, common sites of involvement, and imaging presentation are pivotal for making the diagnosis. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of carcinoid tumors involving various organs of the body is important for diagnosis and patient management. ^©RSNA, 2017.

The mesentery: structure, function, and role in disease

Systematic study of the mesentery is now possible because of clarification of its structure. Although this area of science is in an early phase, important advances have already been made and opportunities uncovered. For example, distinctive anatomical and functional features have been revealed that justify designation of the mesentery as an organ. Accordingly, the mesentery should be subjected to the same investigatory focus that is applied to other organs and systems. In this Review, we summarise the findings of scientific investigations of the mesentery so far and explore its role in human disease. We aim to provide a platform from which to direct future scientific investigation of the human mesentery in health and disease.