Successful treatment of insulinoma by a single daily dose of octreotide in two elderly female patients

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.

Clinical Characteristics and Incidences of Benign and Malignant Insulinoma Using a National Inpatient Database in Japan

CONTEXT

Insulinoma is the most common pancreatic functional neuroendocrine neoplasm, yet little information on recent clinical practice in patients with insulinoma, especially malignant insulinoma, is available.

OBJECTIVE

This work aims to clarify the characteristics and practice patterns in patients with insulinoma using a national inpatient database.

METHODS

Using the Japanese Diagnosis Procedure Combination database, we retrospectively identified patients with insulinoma admitted between 2010 and 2018. We compared background characteristics and therapeutic interventions between patients with benign and malignant insulinoma. We also estimated the incidence of insulinoma using the number of patients with newly diagnosed insulinoma in 2012.

RESULTS

We identified 844 patients with benign insulinoma and 102 patients with malignant insulinoma. Patients with malignant insulinoma were younger (median, 55.5 vs 66.0 years, P < .001) and less likely to be female (55.9% vs 65.3%, P = .061) than patients with benign insulinoma. Analysis of therapeutic interventions revealed that patients with malignant insulinoma more frequently received medications (71.6% vs 49.6%, P < .001) but less frequently underwent pancreatic surgery (57.8% vs 72.0%, P = .003). Older patients were a smaller proportion of those undergoing surgery and a larger proportion of those managed with medications without surgery (P < .001). The incidence of insulinoma was estimated to be 3.27 (95% CI, 2.93-3.61) individuals per million Japanese adult population per year.

CONCLUSION

The present study using a nationwide database had a larger sample size than previous studies and revealed definitive differences in patient characteristics and therapeutic patterns between benign and malignant insulinoma.

Lanreotide and diazoxide have comparable effects on glucose levels in an elderly Japanese insulinoma patient: a case report

An insulinoma is a pancreatic neuroendocrine tumor that causes hypoglycemia. In the elderly, as surgery is not always possible, drugs are an important alternative. However, the effects of lanreotide on insulinomas have not yet been elucidated. We report the case of an 85-year-old Japanese woman who was admitted for loss of consciousness and hypoglycemia, which was resolved after intravenous glucose infusion. Insulin secretion was not inhibited during hypoglycemia. Enhanced computed tomography and OctreoScan scintigraphy revealed a pancreatic tumor (diameter, 13 mm) with radiotracer accumulation. Thus, clinical insulinoma was confirmed. However, the patient refused further examination and surgery. Diazoxide (150 mg/day) therapy resolved hypoglycemia but caused fluid retention. Consequently, we switched to lanreotide (120 mg/6 weeks). Continuous glucose monitoring revealed that both drugs had comparable effects on interstitial glucose normalization. Furthermore, 447 days after the initiation of lanreotide treatment, the patient had no hypoglycemic symptoms. Therefore, lanreotide may be a useful alternative treatment option for inoperable insulinomas in elderly individuals.

Case Report and Literature Review of Insulinoma in the Geriatric Population: An 86-Year-Old Female with Syncope of Unknown Origin

Insulinomas are extremely rare pancreatic endocrine tumors. The tumor is characterized by endogenous hypersecretion of insulin and ensuing development of symptoms of neuroglycopenia and the catecholaminergic response. Symptoms may not always be present, particularly in patients compensating appropriately with increased appetites and caloric intake due to low glucose levels. Early localization of the disease is essential to prevent lethal hypoglycemia and timely treatment. This case report and literature review depict the case of a pancreatic insulinoma in an 86-year-old female, an exceptionally rare presentation based on age and absence of clinical symptoms for one or more years prior to hospitalization. Despite its rarity, similar presentations have been reported in the literature and are further outlined with characteristics and treatment plans. This case highlights a unique presentation of insulinoma and suggests the need for clinical vigilance and further study. It also discusses diagnosis, localization, and management of this uncommon disease in patients above the age of seventy-five.

Uncommon Manifestation of Hypoglycemia in a Patient with Insulinoma – A Case Report

Insulinoma are insulin-secreting tumors of pancreatic origin that generates hypoglycemia by excessive secretion of insulin. Insulinoma is a rare disease ant the most tumors are benign, solitary and occur at intrapancreatic sites.

Case report. A 42-year old Caucasian women was hospitalized at the “Prof. N.C. Paulescu” National Institute of Diabetes, Nutrition and Metabolic Diseases Bucharest in April 2019 after an episode of hypoglycaemia remitted after intravenous glucose administration. Patient accused for about two weeks anxiety phenomena. At the time of admission in the hospital the patient was conscious in a good general condition. Paraclinical investigations revealed basal blood glucose 29 mg/dl, fasting insulin serum 87.7 µU/ml and pancreatic C-peptide-7.90 ng/ml. During hospitalization under strict glycaemic monitoring, the patient presented frequent asymptomatic hypoglycemic episodes that was remitted after intravenous glucose administration. Nuclear magnetic resonance highlighted a nodular lesion of the pancreas and in May 2019 the tumor resection was practiced. After surgery the blood glucose ranged between 86 mg/dl and 116 mg/dl. To mention that patient has a family history of diabetes and she’s obese.

Conclusion. This case suggests that lack symptoms of hypoglycaemia may be present in patients with insulinoma. Diagnostic of insulinoma requires high clinical suspicions, accurate biochemical investigations and imaging techniques for the localization of the tumor and may represent a challenge in certain situations.

Surgery in overweight patients with insulinoma: effects on weight loss

OBJECTIVE

Weight loss induced by the complete resection of insulinoma is controversial in overweight patients. The study sought to explore postoperative weight loss and metabolic changes in overweight insulinoma patients.

METHODS

A retrospective study was conducted to review the follow-up data of insulinoma patients with a BMI ≥25kg/m² who underwent complete lesion resection between May 2010 and May 2015. Body mass index (BMI), weight loss (WL) and percentage weight loss (%WL) were main outcomes.

RESULTS

Fifty-one patients were included with a median follow-up of 28 months. The BMI at 3 months, 1 year, 2 years and 3 years postoperatively were significantly lower than the preoperative BMI values (p < .01). The WL% was 12.9% at 3 months postoperatively without significant changes throughout the 3-year follow-up. WL and the %WL were significantly higher in the high BMI group (BMI≥ 27.5 kg/m²). Multivariate analysis indicated that higher initial BMI was associated with increased weight loss (p = .001). 63.8% of patients with hypertension recovered and improved sleep quality was evident in all patients with obstructive sleep apnea syndrome within 1 year postoperatively.

CONCLUSIONS

Weight significantly decreased postoperatively in overweight insulinoma patients, which was more evident in patients with higher BMI and metabolic comorbidities were largely improved.

Usefulness of the octreotide test in Japanese patients for predicting the presence/absence of somatostatin receptor 2 expression in insulinomas

We investigated the relationship between the results of the octreotide test and somatostatin receptor (SSTR) 2 expression in insulinoma patients, to evaluate the usefulness of this test for predicting SSTR2 expression in insulinomas in Japanese patients. Five females and one male were included in the study. All patients underwent the octreotide test before the surgery carried out to resect the tumor, and histopathological examination of the resected tumor was performed by a single experienced pathologist. SSTR2 expression was evaluated by the SSTR2 immunohistochemistry scoring system. Insulinoma was clinically diagnosed and surgically resected in all six patients. In the octreotide test, suppression of insulin secretion was sufficient after loading in patients 1-4 and 6. In patient 5, however, the suppression of insulin secretion was insufficient, which resulted in severe hypoglycemia with endogenous relative hyperinsulinemia after the octreotide loading. The histopathological findings revealed SSTR2 expression in the insulinomas of patients 1-4 and 6, but not in the insulinoma of patient 5. In conclusion, improvement of hyperinsulinemic hypoglycemia by octreotide in Japanese insulinoma patients was associated with SSTR2 expression in the tumor. Our results suggest that the octreotide test could be useful for predicting SSTR2 expression in the tumor.

Insulinoma in a patient with chronic renal failure due to type 2 diabetes mellitus treated effectively with diazoxide

A 63-year-old man was diagnosed with diabetes mellitus at 42 years of age. He subsequently exhibited poor blood glucose control for a prolonged period, and his renal failure worsened. He therefore underwent hemodialysis and abdominal magnetic resonance imaging, which revealed a mass in the pancreatic tail. The immunoreactive insulin and C-peptide immunoreactivity levels were significantly elevated, and the results of a fasting test led to a diagnosis of insulinoma. The patient received treatment with oral diazoxide and continuous glucose monitoring (CGM), which resulted in the resolution of the hypoglycemia. This is a rare case of renal failure in which the CGM findings showed improvements in the blood glucose level after diazoxide administration.

Combined biological therapy with lanreotide autogel and cabergoline in the treatment of MEN-1-related insulinomas

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome associated with the development of many endocrine tumors, involving mainly pituitary, parathyroids, pancreas, although a proliferative state interests all neuroendocrine system. MEN1 pancreatic neuroendocrine tumors (pNETs) are multiples and can secrete different hormones. The therapeutic approach is based on surgery which usually is followed by tumor relapse or persistence unless to be highly aggressive. Biotherapy with somatostatin analogs and dopamine agonists could be of great benefit to manage these patients without altering their life quality. We report a case of a 36-year-old MEN1 man affected with multicentric pNETs associated with insulinoma syndrome. Therapy with symptomatic agents (diazoxide), as well as biotherapy (lanreotide, cabergoline) was started. At 6-month follow-up, symptomatic agents were stopped and disease control was only based on lanreotide plus cabergoline. This combined biotherapy was able to control endocrine syndromes and tumor growth. Subsequently, a safer and selective surgical intervention on pNETs was performed. An excellent response to therapy with lanreotide autogel and cabergoline has been observed in a MEN1 patient with pNETs associated with insulinoma syndrome. The potential synergistic effects of lanreotide autogel and cabergoline on insulin-secreting neuroendocrine tumors are discussed.

Metastatic insulinoma managed with radiolabeled somatostatin analog

Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium ((177)LU).

Diagnosis and management of insulinoma

Insulinomas, the most common cause of hypoglycemia related to endogenous hyperinsulinism, occur in 1-4 people per million of the general population. Common autonomic symptoms of insulinoma include diaphroresis, tremor, and palpitations, whereas neuroglycopenenic symptoms include confusion, behavioural changes, personality changes, visual disturbances, seizure, and coma. Diagnosis of suspected cases is based on standard endocrine tests, especially the prolonged fasting test. Non-invasive imaging procedures, such as computed tomography and magnetic resonance imaging, are used when a diagnosis of insulinoma has been made to localize the source of pathological insulin secretion. Invasive modalities, such as endoscopic ultrasonography and arterial stimulation venous sampling, are highly accurate in the preoperative localization of insulinomas and have frequently been shown to be superior to non-invasive localization techniques. The range of techniques available for the localization of insulinomas means that blind resection can be avoided. Intraoperative manual palpation of the pancreas by an experienced surgeon and intraoperative ultrasonography are both sensitive methods with which to finalize the location of insulinomas. A high proportion of patients with insulinomas can be cured with surgery. In patients with malignant insulinomas, an aggressive medical approach, including extended pancreatic resection, liver resection, liver transplantation, chemoembolization, or radiofrequency ablation, is recommended to improve both survival and quality of life. In patients with unresectable or uncontrollable insulinomas, such as malignant insulinoma of the pancreas, several techniques should be considered, including administration of ocreotide and/or continuous glucose monitoring, to prevent hypoglycemic episodes and to improve quality of life.

Short- and long-term somatostatin analogue treatment in patients with hypoglycaemia related to endogenous hyperinsulinism

BACKGROUND

The long-term efficacy of somatostatin analogues on insulinomas has not been studied.

DESIGN

A prospective study to evaluate the response of octreotide in 21 patients with hypoglycaemia related to endogenous hyperinsulinism who were not treated by surgery.

RESULTS

Reasons for not undergoing surgery were: refusal (n = 3), old age with multiple diseases (n = 5), unlocalized insulinomas (n = 2), malignant unresectable insulinomas (n = 5), multiple insulinomas (n = 3) and diffuse beta-cell disease (n = 3). Hypoglycaemia was responsive to octreotide in 14 of the 21 patients. A short 100-microg octreotide test correctly predicted the efficacy of treatment in six patients with benign insulinomas. Octreoscan scintigraphy was positive in 6 of the 16 patients of whom three were responsive and three unresponsive to octreotide. Octreoscan scintigraphy was negative in 10 of the 16 patients, eight of whom were responsive to octreotide. Subcutaneous octreotide treatment was prolonged for > 6 months (7-144 months, 67 +/- 47 months) in 11 responsive patients. No tachyphylaxis was observed. However, the octreotide dose had to be increased in two patients after 3 and 18 months, respectively. Only one patient suffered from symptomatic biliary lithiasis after 3 years of treatment.

CONCLUSION

Long-term octreotide treatment can be used to control hypoglycaemia in patients with endogenous hyperinsulinism who are not eligible for surgery; octreotide efficacy on hypoglycaemia could be predicted by a short 100 microg-octreotide test in patients with benign insulinomas, but was not correctly predicted by Octreoscan scintigraphy.