Nationwide registry for patients with neuroendocrine neoplasm of pancreas, gastrointestinal tract, lungs, bronchi, or thymus in Japan

Case Report: A case of occult insulinoma localized by [18F] FB (ePEG12)12-exendin-4 positron emission tomography with negative findings of selective arterial calcium stimulation test

Background

Insulinomas, the most common functional pancreatic neuroendocrine tumors, cause hypoglycemia due to excessive insulin production, leading to severe clinical symptoms like coma or death. Resection surgery is the major curative treatment, but preoperative localization is challenging due to their small size. Traditional imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI) often fail to detect tumors, while more invasive procedures like endoscopic ultrasound tissue acquisition (EUS-TA) and the selective arterial calcium stimulation test (SACST), though informative, depend heavily on operator skill and may not always provide conclusive results. There is an urgent need for non-invasive, sensitive localization methods for insulinomas. Glucagon-like peptide 1 receptor (GLP-1R) targeted PET imaging has emerged as a promising tool. We present a clinical case where [18F] FB (ePEG12)12-exendin-4 positron emission tomography/CT (18F-exendin-4 PET/CT) successfully detected insulinoma, unachievable by conventional imaging, underscoring its potential in guiding minimally invasive surgery.

Case description

A 67-year-old female developed hyperinsulinemic hypoglycemia but could not undergo surgery as conventional imaging methods failed to localize the insulinoma. She was managed with diazoxide for six years, but her symptoms worsened. At 73, she was referred to our hospital. CT, MRI, endoscopic ultrasound, and SACST failed to detect the tumor in any artery. However, 18F-exendin-4 PET/CT revealed a nodule with uptake in the dorsal pancreas, suspected to be the culprit lesion. The patient underwent surgery, and although the tumor appeared discontinuous with the pancreas macroscopically, histopathology confirmed it was microscopically continuous, identifying it as a primary pancreatic insulinoma. Post-surgery, she achieved complete remission of symptoms and fully recovered.

Discussion

This case demonstrates the utility of 18F-exendin-4 PET/CT, a novel GLP-1 receptor-targeted imaging technique, in accurately localizing an occult insulinoma even with negative findings of SACST, enabling minimally invasive curative surgery.

Conclusion

The 18F-exendin-4 PET/CT successfully localized an insulinoma undetectable by other methods, enabling minimally invasive curative resection. This technique offers a valuable diagnostic option for enabling minimally invasive surgery in occult insulinoma cases.

Evaluation of the details and importance of lymphatic, microvascular, and perineural invasion in patients with non-functioning pancreatic neuroendocrine neoplasms based on tumor size and the 2022 World Health Organization classification: a 23-year retrospective analysis

BACKGROUND

Although, recently observation methods has been proposed as one of the treatment options for non-functioning pancreatic neuroendocrine neoplasms (NF-PanNENs), determining treatment strategies may be difficult for small and low-malignant NF-PanNENs; thus, clarifying the significance of lymphatic, microvascular, and perineural invasion in these patients is of great clinical importance. This study aimed to assess the incidence and role of lymphatic, microvascular, and perineural invasion in patients with NF-PanNENs based on tumor size and the 2022 World Health Organization classification.

METHODS

From 2000 to 2023, we retrospectively investigated the incidence of lymphatic, microvascular, and perineural invasion and their impact on recurrence in 80 patients who underwent curative resection and were diagnosed with NF-PanNENs.

RESULTS

Of the 80 patients, 14 (18%), 20 (25%), and six (9%) patients had lymphatic, microvascular, and perineural invasion. Patients with neuroendocrine tumor (NET) G1 had significantly fewer occurrences of lymphatic, microvascular, and perineural invasion than those with NET G2 (10%, 15%, and 7% vs. 40%, 55%, and 35%; all P < 0.05.). Patients with a tumor size < 20 mm had significantly lower rates of lymphatic and microvascular invasions than those with a tumor size ≥ 20 mm (12% and 17% vs 33% and 48%; P = 0.034 and 0.0073, respectively). In all patients, NET G2, tumor size ≥ 20 mm, local invasion T2-3, presence of lymph node metastasis, and presence of microvascular invasion were significant risk factors for shorter recurrence-free survival (RFS) (all P < 0.05). In patients with NET G1 and tumor size < 20 mm, five (10%), eight (16%), and four (8%) patients had lymphatic, microvascular, and perineural invasion. The presence of microvascular invasion was also an independent risk factor for RFS (P < 0.05).

CONCLUSIONS

Information on the frequency and role of lymphatic, microvascular, and perineural invasion based on tumor size and malignancy on recurrence may be useful when considering treatment strategies for small- and low-grade NF-PanNENs.

Liver transplantation for gastroenteropancreatic neuroendocrine liver metastasis: optimal patient selection and perioperative management in the era of multimodal treatments

Gastroenteropancreatic neuroendocrine tumors (NET) often metastasize to the liver. Although curative liver resection provides a favorable prognosis for patients with neuroendocrine liver metastasis (NELM), with a 5-year survival rate of 70-80%, recurrence is almost inevitable, mainly in the remnant liver. In Western countries, liver transplantation (LT) has been performed in patients with NELM, with the objective of complete removal of macro- and micro-NELMs. However, prognosis had been unsatisfactory, with 5-year overall survival and recurrence-free survival rates of approximately 50 and 30%, respectively. In 2007, the Milan criteria were proposed as indications for LT for NELM. The criteria included: (1) confirmed histology of NET-G1 or G2; (2) a primary tumor drained by the portal system and all extrahepatic diseases removed with curative resection before LT; (3) liver involvement ≤50%; (4) good response or stable disease for at least 6 months before LT; (5) age ≤ 55 years. A subsequent report demonstrated outstanding LT outcomes for NELM within the Milan criteria, with 5-year overall survival and recurrence rates of 97 and 13%, respectively. In Japan, living donor LT (LDLT) for NELM has been performed sporadically in only 16 patients by 2021 in Japan; however, no consensus has been reached on the indications or perioperative management of LDLT. This article presents the outcomes of these 16 patients who underwent LDLT in Japan and reviews the literature to clarify optimal indications and perioperative management of LDLT for NELM in the era of novel multimodal treatments.

An ACTH-Producing Neuroendocrine Tumor: Clinical Course of Multidisciplinary Therapy Including Peptide Receptor Radionuclide Therapy - A Case Report

Introduction

Clinical experiences of peptide receptor radionuclide therapy (PRRT) in patients with adrenocorticotropic hormone (ACTH) producing neuroendocrine tumor (NET) were extremely rare.

Case Presentation

A 60-year-old woman with hypertension, lower-extremity edema, hypoalbuminemia, hypokalemia, and multiple hepatic tumors was hospitalized for further examination and treatment. Endocrine testing detected excessive levels of ACTH and cortisol in her blood. Pathohistological examination revealed the hepatic lesions to be ACTH-positive grade 2 NETs (G2). A diagnosis of ectopic ACTH-producing NET was made. The patient was initially treated with the 11-hydroxylase inhibitor, metyrapone, to control hypercortisolemia and the long-acting somatostatin analog, lanreotide. Simultaneously, everolimus was continued for about 1 year. Subsequently, hepatic tumors were surgically resected, leading to successful and rapid normalization of ACTH secretion and resolution of hypercortisolemia. However, the disease relapsed and presented with multiple hepatic masses and increased ACTH 18 months after surgery. As sunitinib and subsequent streptozocin chemotherapy failed to control the disease, PRRT with 177Lu-DOTATATE was performed. ACTH levels increased after initiation of PRRT, and clinical manifestations, such as pigmentation, hypertension, and hyperglycemia, were remarkable. The patient was treated with antihypertensive and antidiabetic agents, and required an increased dose of metyrapone and addition of the cortisol biosynthesis inhibitor, osilodrostat. After four cycles of PRRT, the hepatic tumors showed a remarkable reduction in size with normalization of ACTH level and withdrawal of cortisol synthesis inhibitors.

Conclusion

Although PRRT was effective, we should consider the occurrence of hormonal crisis during the therapy. Due to the rarity and complexity of hormone-producing tumors, cooperation between medical oncologists and endocrinologists is important for patient management.

The importance of microvascular invasion in patients with non-functioning pancreatic neuroendocrine neoplasm

BACKGROUND/OBJECTIVES

The oncological importance of lymphatic, microvascular, and perineural invasions and their association with outcomes in patients with non-functioning pancreatic neuroendocrine neoplasm (NF-PanNEN) remains unclear. We aimed to investigate the role of these factors in the prognosis of patients with NF-PanNEN.

METHODS

We retrospectively analyzed 115 patients who underwent curative resection and were pathologically and clinically diagnosed with NF-PanNEN. We evaluated the relationship between clinicopathological factors and recurrence.

RESULTS

Thirty (26%), 38 (33%), and 11 (10%) patients had lymphatic, microvascular, and nerve invasions, respectively. Twenty-one patients (18%) experienced recurrence, with a median time to recurrence of 2.6 years (range: 0.3-8.2). The 3-, 5-, and 10-year recurrence-free survival (RFS) rates were 88.3%, 84.4%, and 79.1%, respectively. In multivariate analyses, World Health Organization Grade G2-3 (vs. G1, hazard ratio (HR): 16.2), T factor T3-4 (vs. T1-2, HR: 5.2), and the presence of microvascular invasion (vs. absence, HR: 5.6) were significant risk factors for RFS. When these risk factors were assigned as risk score of three, one, and one points depending on the HR, the 5-year recurrence rates in patients with risk score groups 0-1 and 2-5 were 98.6% and 53.3%, (P < 0.001). Moreover, only the presence of microvascular invasion significantly increased the likelihood of recurrence within 3 years.

CONCLUSIONS

The presence of microvascular invasion is an independent risk factor for recurrence in patients with NF-PanNEN. Our risk scoring system, which includes "the presence of microvascular invasion," may be useful for predicting recurrence.

Hypovascular insulinoma with reduced microvessel density on histopathology: a case report

Pancreatic neuroendocrine tumors (PanNETs) are generally hypervascular and readily detectable on imaging tests. However, hypovascular PanNETs are clinically problematic, requiring multiple imaging tests and tissue analyses to differentiate them from pancreatic ductal cancers. A 41 year-old man presented with Whipple's triad; 72 h fasting test followed by glucagon challenge test suggested insulinoma. However, contrast-enhanced computed tomography image showed a 17 mm tumor with poor enhancement and unclear borders in the tail of the pancreas. Abdominal magnetic resonance imaging and contrast-enhanced endoscopic ultrasonography (EUS) indicated cystic degeneration and necrosis at the same site; EUS-guided fine-needle aspiration cytology indicated a PanNET Grade 1 tumor. Although the imaging was inconclusive, diazoxide treatment ameliorated the hypoglycemia-related symptoms and insulinoma was deemed likely; following tail pancreatectomy and splenectomy, the symptoms disappeared. Pathological examination revealed a tumor positive for insulin and classed as PanNET Grade 1 according to the 2019 WHO classification. The microvessel density (MVD) of the tumor was found to be as low as 3.9%, which may partly account for the inconclusive images. The present case was difficult to diagnose preoperatively due to hypovascularity on imaging because of reduced MVD. It is clinically important to evaluate MVD in cases of hypovascular PanNETs by multiple preoperative imaging studies to differentiate them from pancreatic cancers and to validate the findings by postoperative pathological analysis.

[18F]FB(ePEG12)12-exendin-4 noninvasive imaging of insulinoma negative for insulin immunostaining on specimen from endoscopic ultrasonography-guided fine needle aspiration: a case report with review of literature

Insulinomas are the most common functional pancreatic neuroendocrine neoplasm; when treatment is delayed, they induce hyperinsulinemic hypoglycemia, which is life-threatening. As surgical resection is the only curative treatment for insulinoma, preoperative localization is crucial; however, localization based on conventional imaging modalities such as computed tomography (CT) and magnetic resonance imaging is often inconclusive. Somatostatin receptor-targeted imaging is another option for detecting pancreatic neuroendocrine neoplasms but has low sensitivity and is not specific for insulinoma. The clinical application of other localizing approaches such as selective arterial calcium stimulation and endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is limited by their being invasive and/or technically complex. Moreover, an EUS-FNA specimen of an insulinoma may be negative on insulin immunostaining. Thus, a noninvasive and clinically practical insulinoma-specific diagnostic tool to discriminate insulinomas with high accuracy is anticipated. Glucagon-like peptide-1 receptor (GLP-1R)-targeted imaging has emerged in the effort to fulfill this need. We recently developed the novel fluorine-18-labeled exendin-4-based probe conjugated with polyethylene glycol, [18F]FB(ePEG12)12-exendin-4 (18F-exendin-4) for positron emission tomography (PET) imaging and reported its clinical benefit in a case of insulinoma in the pancreatic tail. We report here a case of insulinoma in the pancreatic head in which an EUS-FNA specimen was negative on insulin immunostaining while precise preoperative localization and conclusive evidence for curative enucleation was provided by 18F-exendin-4 PET/CT (Japan Registry of Clinical Trials; jRCTs051200156).

A case of insulinoma misidentified as schizophrenia due to its manifestation in neuropsychiatric symptoms

Insulinomas can present with neuroglycopenic symptoms suggesting neuropsychiatric disorders, delaying diagnosis and treatment. We recently treated a 65-year-old woman with insulinoma who was misdiagnosed at her nearby psychiatric clinic as having schizophrenia because of personality changes and memory impairment; she was treated with brexpiprazole, which was discontinued due to persistence of the symptoms. Despite her relatively low casual plasma glucose (70 mg/dL), the physician at the psychiatric clinic did not investigate the possibility of hypoglycemia, partly because her HbA1c level (5.2%) was within normal range. After skipping lunch one day, she was found by her family to be unable to communicate properly. She was transported to the emergency room of our hospital, where intermittently scanning continuous glucose monitoring (isCGM) use permitted detection of the hypoglycemia and led to a diagnosis of insulinoma and successful resection. A 72-h fasting test established hyperinsulinemic hypoglycemia. Contrast-enhanced computed-tomography and endoscopic ultrasonography together with selective arterial calcium stimulation test revealed an insulin-secreting tumor in the tail of the pancreas. Surgical resection of the tumor corrected her glucose and insulin levels as well as eliminated the insulinoma neuropsychiatric symptoms. Pathological examination showed that the tumor was positive for chromogranin A, synaptophysin and insulin. It is, therefore, important for physicians to be aware that insulinomas can manifest as neuroglycopenic symptoms and to consider the possibility of hypoglycemia by careful medical interview and isCGM, especially when patients suspected of psychiatric disorders do not show the expected response to antipsychotic drugs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-024-00722-9.

Clinicopathological characteristics of gastric neuroendocrine neoplasms: A comprehensive analysis

OBJECTIVE

This study aimed to explore the clinicopathological characteristics and prognostic implications of gastric neuroendocrine neoplasms (g-NENs).

METHODS

A retrospective enrollment of 142 patients diagnosed with g-NENs was conducted at Zhejiang Cancer Hospital between January 1, 2007 and December 31, 2021. The study compared essential clinicopathological features and survival rates. Additionally, the prognosis of gastric neuroendocrine carcinomas/mixed neuroendocrine-non-neuroendocrine neoplasms (g-NEC/MiNEN) were contrasted with those of gastric adenocarcinoma (GAC) and signet ring cell carcinoma (SRCC).

RESULTS

The study comprised a total of 142 g-NENs cases, with a male-to-female ratio of approximately 2:1. The 5-year survival rates for g-NEC and g-MiNEN were 26.7% and 35.2%, respectively. Corresponding 5-year survival rates for G1 and G2 were observed at 100% and 80.0%, respectively. g-NEC/MiNEN showed a significantly worse prognosis compared to g-NET (p < 0.001). g-NEC/MiNEN exhibited a poor prognosis compared to GAC (p < 0.001), and within poorly differentiated GAC, g-NEC/MiNEN demonstrated a worse prognosis (p = 0.007). Additionally, patients receiving postoperative adjuvant therapy exhibited notably prolonged overall survival (OS) in the case of g-NEC/MiNEN (p = 0.010).

CONCLUSION

In short, the prognosis of g-NEC/MiNEN was worse than that of g-NET, GAC and poorly differentiated GAC, but this group benefit from postoperative adjuvant therapy.

18F-labeled PEGylated exendin-4 imaging noninvasively differentiates insulinoma from an accessory spleen: the first case report of [18F]FB(ePEG12)12-exendin-4 positron emission tomography/computed tomography for insulinoma

Background

Insulinomas are the most common functioning pancreatic neuroendocrine neoplasms, and these tumors induce hypoglycemia due to hyperinsulinemia. Hypoglycemia caused by insulinomas can cause seizures, coma or death due to the delayed diagnosis. The only curative treatment is surgical resection. To perform curative surgical resection of insulinomas, preoperative localization is crucial. However, localization of insulinomas is often challenging using conventional imaging methods such as computed tomography (CT) and magnetic resonance imaging. Although endoscopic ultrasound (EUS) fine-needle aspiration and selective arterial calcium stimulation test, which can reflect the endocrine character of the tumor, are performed in such cases, these modalities are invasive and require operator-dependent techniques. Additionally, somatostatin receptor (SSTR)-targeted imaging has a relatively low sensitivity for detecting insulinomas due to its low SSTR type 2 expression. Thus, there is an urgent need for developing a noninvasive diagnostic technique which is specific for detecting insulinomas. Consequently, glucagon-like peptide-1 receptor-targeted imaging has recently emerged and gained a wide interest. Recently, we have developed a novel 18F-labeled exendin-4-based probe conjugated with polyethylene glycol, [18F]FB(ePEG12)12-exendin-4 (18F-exendin-4), for positron emission tomography (PET) imaging. Here we report a case of insulinoma in which 18F-exendin-4 PET/CT noninvasively provided critical information for localization.

Case description

This is a case of a 58-year-old male with symptomatic hypoglycemia for 10 years; however, a preoperative diagnosis of insulinoma was not established due to the difficulty in differentiating it from an accessory spleen using conventional imaging. Moreover, the patient requested to avoid invasive diagnostic procedures including EUS. 18F-exendin-4 PET/CT revealed significant uptakes in the pancreatic tail whereas no apparent uptakes were observed in the spleen; thus, curative laparoscopic enucleation of the pancreatic tail was performed. The diagnosis of insulinoma was confirmed via histopathological examination. This is the first case report of insulinoma diagnosed using 18F-exendin-4 PET/CT.

Conclusion

In this case, PET information led to curative resection through enucleation of the pancreas. 18F-exendin-4 PET/CT may serve as a useful noninvasive clinical tool for insulinoma localization.

Unmasked insulinoma occasioned by severe hypoglycemic coma immediately postpartum: a case report

BACKGROUND

Insulinoma in women during pregnancy and postpartum is very rare; approximately 65% of cases are diagnosed early in pregnancy and ~ 35% immediately after delivery, few being found in middle or late pregnancy, likely due to increased insulin resistance seen after early-stage pregnancy. We successfully treated a case of insulinoma in which severe hypoglycemic coma immediately after delivery occasioned detailed investigation and diagnosis.

CASE PRESENTATION

Our patient experienced hypoglycemic coma in the 3rd month of pregnancy (initially considered due to her hyperemesis gravidarum) that improved spontaneously during the gestational period. No abnormalities of plasma glucose or body weight were found in regular checkups during her pregnancy; however, recurrence of hypoglycemic coma after delivery led us to suspect insulinoma. While contrast enhanced computer tomography and endoscopic ultrasonography (EUS) initially failed to detect a tumor in the pancreas, selective arterial calcium stimulation test revealed an insulin-secreting tumor localized in the pancreatic body. She then underwent spleen-preserving distal pancreatectomy; a 10-mm tumor positive for chromogranin A, synaptophysin and insulin was identified.

CONCLUSIONS

Although pregnancy can mask insulinoma-associated symptoms and make diagnosis challenging, hypoglycemic episodes during early pregnancy, which were observed in this case, are suggestive of insulinoma. Importantly, in this case, accurate preoperative localization of the tumor enabled prompt curative surgery after delivery. Thus, clinical vigilance for the occurrence of insulinoma and its localization is appropriate for pregnant women suffering severe hypoglycemia.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (64Cu-DOTATATE or 68Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.