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

Metastatic insulinoma presenting after bariatric surgery in a patient diagnosed with MEN1

Insulinomas are uncommon neuroendocrine tumors and metastatic disease is extremely rare. We report a patient with metastatic insulinoma associated with multiple endocrine neoplasia type 1 presenting with hypoglycemia following sleeve gastrectomy. Potential causes of hypoglycemia include dumping syndrome, noninsulinoma pancreatogenous hypoglycemia syndrome, and rarely insulinoma. MEN1‐associated insulinomas have a higher recurrence rate.

Management of asymptomatic, well-differentiated PNETs: results of the Delphi consensus process of the Americas Hepato-Pancreato-Biliary Association

BACKGROUND

Variation in the management of PNETs exist due to the limited high-level evidence to guide clinical practice. The aim of this work is to generate consensus guidelines with a Delphi process for managing PNETs.

METHODS

A panel of experts reviewed the surgical literature and scored a set of clinical case statements using a web-based survey to identify areas of agreement and disagreement. Results of the survey were discussed after each round of review. This cycle was repeated until no further likelihood of reaching consensus existed.

RESULTS

Twenty-two case statements related to surgical indications, preoperative biopsy, extent of resection, type of surgery, and tumor location were scored. Using a pre-defined definition of consensus, the panel achieved consensus on the following: i) resection is not recommended for <1 cm lesions; ii) resection is recommended for lesions greater than 2 cm; iii) lymph node dissection is recommended for radiographically-suspicious nodes with splenectomy for distal lesions; iv) tumor enucleation and central pancreatectomy are acceptable when technically feasible. No consensus was reached regarding issues of preoperative biopsy or 1-2 cm tumors.

CONCLUSIONS

Using a structured, validated system for identifying consensus, an expert panel identified areas of agreement regarding critical management decisions for patients with PNET. Issues without consensus warrant additional clinical investigation.

A case of insulin and ACTH co-secretion by a neuroendocrine tumour

A 33-year-old male was diagnosed with a metastatic neuroendocrine carcinoma of uncertain primary. He defaulted from follow-up without therapy and some months later developed episodic severe hypoglycaemia, which was found to be associated with inappropriately elevated insulin and C-peptide levels. It was considered likely that the neuroendocrine tumour was the source of the insulin secretion. Diazoxide and somatostatin analogue were used to control hypoglycaemia. Much later in the course of the disease, he developed metabolic derangement, increased skin pigmentation and psychological disturbance, without frankly Cushingoid physical findings. Investigations revealed highly elevated cortisol levels (the levels having previously been normal) with markedly raised ACTH levels, consistent with the co-secretion of ACTH and insulin by the tumour. Treatment with metyrapone improved his psychological state and electrolyte imbalance. Unfortunately, despite several cycles of first-, second- and third-line chemotherapy from the start of the first hormonal presentation onwards, imaging revealed widespread progressive metastatic disease and the patient eventually passed away. This case highlights the importance of keeping in mind the biochemical heterogeneity of endocrine tumours during their treatment.

LEARNING POINTS

The clinical presentation of insulin-secreting tumours includes symptoms of neuroglycopaenia and sympathetic overstimulation.Tumour-associated hypoglycaemia can be due to pancreatic insulinomas, and although ectopic hormone production occurs in a number of tumours, ectopic secretion of insulin is rare.A possible switch in the type of hormone produced can occur during the growth and progression of neuroendocrine tumours and, when treating neuroendocrine tumours, it is important to keep in mind their biochemical heterogeneity.

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.