Insulinoma accompanied by diabetes mellitus

Insulinoma in Patients with Diabetes- A Systematic Review of Previously Reported Cases

Introduction

Paradoxical co-existence of insulinoma and diabetes is extremely rare. Although a few case reports addressed this association, a comprehensive study elucidating this relationship has been lacking. We performed a systematic review of published cases of insulinoma in diabetes.

Methods

We conducted a literature search using PubMed and Google Scholar, employing various combinations of the following terms: 'insulinoma', 'diabetes', 'nesidioblastosis', 'endogenous hyperinsulinism', 'hypoglycaemia', and 'hyperglycaemia' (from January 1900 to January 30, 2024). Exclusion criteria included non-English publications, duplicate articles, reports lacking sufficient data, cases of endogenous hyperinsulinemic hypoglycaemia other than insulinoma, and inaccessible articles. Statistical analysis was performed using appropriate methods.

Results

Sixty patients were considered for the final analysis. Mean age was 61 ± 15 years (range: 17-96 years) with a slight female preponderance; 88.3% had type-2 diabetes with a median duration of 8 years. The median delay in diagnosis of insulinoma was 6 months. Median blood glucose varied from 30.5 mg/dL to 235 mg/dL, with a mean HbA1c of 5.6 ± 1.3% (range: 2.9%-8.2%). Critical sampling data were available in 75% of cases. The median size of the insulinoma was 2 cm. Furthermore, 5.2% of insulinomas were extra-pancreatic. Among pancreatic insulinomas, 14.5% were multi-focal. One-third of cases were malignant. Surgical resection was done in 70.9% of cases, while 40% received drug therapy and 12.7% received both, with 20.7% overall mortality. Malignant insulinoma (P = 0.007), micro-angiopathic (P = 0.018) and macro-angiopathic complications (P = 0.039), and other co-morbidities (P = 0.009) were associated with unfavourable prognosis, while being overweight and obese (P = 0.020) at presentation was associated with favourable prognosis.

Conclusion

This first systematic review provides insights into the uniqueness of insulinoma in diabetes.

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.

Presentation, diagnostic features and glucose handling in a monocentric series of insulinomas

BACKGROUND

New aspects have emerged in the clinical and diagnostic scenarios of insulinoma: current guidelines have lowered the diagnostic insulin threshold to 3 μU/ml in the presence of hypoglycemia (<55 mg/dl); post-prandial hypoglycemia has been reported as the only presenting symptom; preexisting diabetes mellitus (DM) was recognized in some patients.

AIM

To evaluate clinical features, diagnostic criteria and glucose metabolic profile in a monocentric series of patients affected by insulinomas including two subgroups: sporadic and multiple endocrine neoplasia type-1 syndrome (MEN-1).

SUBJECTS AND METHODS

Clinical, pathological and biochemical data regarding 33 patients were analyzed.

RESULTS

following the current guidelines the 72-h fasting test was initially positive in all cases but one. In this case the test, initially negative, became positive after a 2-yr follow-up. Nadir insulin level was ≥ 3 μU/ml but <6 μU/ml in 3 patients and ≥ 6 μU/ml in the remaining 30 cases. At presentation, 27 patients (82%) reported only fasting symptoms, 3 (9%) only post-prandial and 3 (9%) both. Seven cases (21%) had previously been affected by type 2 DM or impaired glucose metabolism.

CONCLUSIONS

In our series the new cut-off of insulin increased the sensitivity of the 72-h fasting test from 87% to 97%. The absence of hypoglycemia during the test cannot definitively rule out the diagnosis and the test should be repeated in every highly suspicious case. Post-prandial hypoglycemia can be the only presenting symptom. DM may be associated with the occurrence of insulinoma. So that a possible diagnosis of insulinoma must not be ignored if previous impaired glucose handling is evident.

GLP-1 and glucagon secretion from a pancreatic neuroendocrine tumor causing diabetes and hyperinsulinemic hypoglycemia

CONTEXT

Glucagon-like peptide-1 (GLP-1) is a gut peptide that promotes insulin release from pancreatic β-cells and stimulates β-cell hyperplasia. GLP-1 secretion causing hypoglycemia has been described once from an ovarian neuroendocrine tumor (NET) but has not been reported from a pancreatic NET (pNET).

OBJECTIVE

A 56-yr-old male with a previous diagnosis of diabetes presented with fasting hypoglycemia and was found to have a metastatic pNET secreting glucagon. Neither the primary tumor nor metastases stained for insulin, whereas the resected normal pancreas showed histological evidence of islet cell hyperplasia. We provide evidence that GLP-1 secretion from the tumor was the cause of hyperinsulinemic hypoglycemia.

METHODS

GLP-1 levels were determined in the patient, and immunohistochemistry for GLP-1 was performed on the tumor metastases. Ex vivo tissue culture and a bioassay constructed by transplantation of tumor into nude mice were performed to examine the tumor secretory products and their effects on islet cell function.

RESULTS

The patient had high levels of glucagon and GLP-1 with an exaggerated GLP-1 response to oral glucose. Immunohistochemistry and primary tissue culture demonstrated secretion of glucagon and GLP-1 from the tumor metastases, whereas insulin secretion was almost undetectable. Ex vivo coculture of the tumor with normal human islets resulted in inhibition of insulin release, and transplanted mice developed impaired glucose tolerance.

CONCLUSIONS

This is the first description of glucagon and GLP-1 secretion from a metastatic pNET causing sequential diabetes and hypoglycemia. Hypoglycemia was caused by insulin secretion from hyperplastic β-cells stimulated by tumor-derived GLP-1.

Type 2 diabetes mellitus in a patient with malignant insulinoma manifesting following surgery

BACKGROUND

Insulinomas, although they are rare, are the most common of pancreatic islet cell tumours. The incidence is estimated at only four per million person-years and only 5-12% of reported cases are malignant. Distinction between malignant and benign tumours can only be made by the presence of metastasis, as there are no specific morphologic, biochemical or genetic features distinguishing them. Most patients with malignant insulinoma have lymph node or liver metastases and, rarely, bone involvement. The coincidence of insulinoma and diabetes mellitus is an extremely rare condition and reported only in a few cases.

CASE REPORT

We report a 45-year-old woman who was diagnosed with insulinoma on the basis of clinical and laboratory findings and endoscopic examination. Histopathological diagnosis revealed well-differentiated endocrine carcinoma of the pancreas with lymph node metastases. The case was accepted as malignant insulinoma and the patient underwent surgery. Interestingly, hyperglycaemia occurred after the removal of the insulinoma, with the requirement for insulin in the post-operative 3 weeks, which was changed to oral anti-diabetic agents as a permanent treatment. The patient is still being treated with oral anti-diabetic agents. We think that the patient might have had diabetes mellitus, because of insulin resistance that developed with a high-caloric intake stimulated by hypoglycaemia, and which had been masked for many years, but manifested overtly after removal of the tumour.

CONCLUSIONS

Although this is a rare condition, clinicians should bear in mind that insulinomas may exist together with diabetes mellitus, and it is important to have this suspicion when considering the perioperative approach and for the prevention of morbidities.

A rare cause of hypoglycemia in a type 2 diabetic patient: insulinoma

Recurrent episodes of hypoglycemia in patients with diabetes are often associated with the ongoing treatment regimen. However, despite changes in treatment modalities, assessment of the causes of hypoglycemia in nondiabetic patients in the presence of severe and recurrent hypoglycemia is very important. The treatment that had been provided for 6 years in a 67-year-old female patient with type 2 diabetes mellitus was discontinued due to hypoglycemic episodes that presented for the previous 2 years. The patient experienced persistent hypoglycemia after cessation of the treatment and was hospitalized for further examination. Spontaneous hypoglycemia with a final diagnosis of insulinoma was established following histopathologic evaluation and was relieved postoperation. Insulinoma is rarely encountered as a cause of hypoglycemia in patients with type 2 diabetes. Insulin-secreting tumors should be considered where hypoglycemic episodes occur despite discontinuation of insulin and other antidiabetic treatment with endogenous hyperinsulinemia being noncompliant with the blood glycemic levels.

Hyperinsulinemic hypoglycemia associated with ectopic Cushing's syndrome due to a pancreatic endocrine tumor in a Type 2 diabetes mellitus patient: clinical implications of a rare association

BACKGROUND

The coexistence of insulin and ACTH hypersecretion in the same patient is extremely rare. A diabetic patient with a pancreatic endocrine tumor (PET) co-secreting insulin and ACTH is even rarer and has never been described. The combination of these two endocrine syndromes results in a peculiar clinical picture.

AIM

To determine the cause of glycemic variations in a patient with previously stable diabetes mellitus.

SUBJECTS AND METHODS

This is a clinical case report from the Endocrinology Unit of Aosta Hospital and Internal Medicine and Surgical Unit of Verona University. A 69-yr-old diabetic patient was hospitalized for recurrent severe hypoglycemic events persistent after withdrawal of anti-diabetic drugs. The causes of hypoglycemia and subsequent resumption of hyperglycemia were investigated.

RESULTS

An insulin-secreting PET was diagnosed. Diazoxide and octreotide therapy initially was able to control hypoglycemic symptoms, then, a Cushing's syndrome occurred resulting in worsening of diabetes control. ACTH was found to be released by the PET previously diagnosed as an insulin-secreting tumor. The tumor was removed and the histology was consistent with a well differentiated endocrine carcinoma. After surgery, adrenal function was normal and insulin therapy was again necessary to control diabetes.

CONCLUSIONS

A single PET may be responsible for both a hyperinsulinemic and a Cushing's syndrome. When this rare association occurs, each of the two syndromes may affect the other resulting in a peculiar clinical course. Finally, an insulin-secreting PET has to be kept in mind as a rare cause of hypoglycemia in diabetic patients.

Overtly manifested diabetes mellitus after resection of insulinoma

Insulinoma is the most common cause of endogenous hyperinsulinemic hypoglycemia in adults. However, the coincidence of insulinoma and diabetes is extremely uncommon. We describe a rare, but very interesting case of diabetes mellitus which was masked by insulinoma and was overtly manifest after the removal of the insulinoma.

Insulinoma Causing Hypoglycemia in a Patient with Type 2 Diabetes

Insulinoma in a patient with pre-existing diabetes is extremely rare. A 74-year-old woman with type 2 diabetes mellitus who had been treated with a sulfonylurea for 6 years began experiencing frequent episodes of hypoglycemia. Endogenous hyperinsulinism was found 9 months after the sulfonylurea was discontinued, and transabdominal ultrasonography and magnetic resonance imaging identified a pancreatic tumor. Pathology examination of the resected tumor demonstrated an insulinoma. Postoperatively, the patient had no further episodes of hypoglycemia. Thereafter, she required insulin to control her hyperglycemia. Although hypoglycemic agents are the commonest cause of hypoglycemia in type 2 diabetes, insulinomas may occur in these patients. This possibility should be considered if the hypoglycemia persists despite dose adjustment or cessation of the drugs.

Insulinoma in a Dog With Pre-existing Insulin-Dependent Diabetes Mellitus

A 10-year-old golden retriever with a 3-year history of insulin-dependent diabetes mellitus was presented with recurring episodes of hypoglycemia and seizures. A presumptive diagnosis of an insulinoma was made based on hypoglycemia with concurrent endogenous hyperinsulinemia and unremarkable radiographic and ultrasonographic images of the chest and abdomen. A beta cell carcinoma of the pancreas with metastasis to the liver and a mesenteric lymph node was confirmed by surgery and histopathology.

Metastatic Malignant Insulinoma in A Patient With Type 2 Diabetes Mellitus: Case Presentation and Literature Review

OBJECTIVE

To describe the occurrence of metastatic malignant insulinoma in a patient with preexisting type 2 diabetes mellitus.

METHODS

We present a detailed case report, with clinical, biochemical, and imaging findings, and summarize the data from 21 similar cases in the literature.

RESULTS

The occurrence of malignant insulinoma in a patient with preexisting diabetes is very rare and thus can be a diagnostic challenge. In our patient with type 2 diabetes, endogenous hyperinsulinism was confirmed by demonstrating elevated insulin and C-peptide levels during hypoglycemic episodes in the absence of sulfonylurea on a blood screen. Abdominal computed tomographic scan and magnetic resonance imaging revealed a pancreatic mass as well as metastatic lesions in the liver. The pancreatic mass was removed and confirmed to be a malignant insulinoma. This procedure was followed by disappearance of the hypoglycemic episodes as well as the diabetes for a few months. On follow-up, however, more metastatic lesions appeared in conjunction with a protracted course of hypoglycemia that necessitated treatment with antihypoglycemic agents and, 3 years after the initial surgical intervention, culminated in the death of the patient.

CONCLUSION

Our patient is one of the few subjects known to have a malignant insulinoma in conjunction with preexisting diabetes. A high degree of suspicion for the presence of an insulinoma should be maintained when unexplained hypoglycemic episodes occur in a patient with previously stable diabetes.