Endocrine Abstracts

Introduction

In the background of persistent hyperinsulinemic hypoglycemia the insulinomas of the pancreatic beta cells may be present, but in some rare cases we fail to identify a well-defined lesion and the insulin hypersecretion is caused by nesidioblastosis, a diffuse proliferation of the pancreatic islet cells. However, the localization of the lesion is necessary for proper treatment, in certain cases finding the insulinoma is difficult and can only be helped by special examination techniques, like selective intraarterial calcium stimulation.

Case report

We report the case of a 36-year-old man who has acoustic neurinoma in his previous history. His present symptoms started one and a half year ago. In the background of collapses, dizziness, agitation, somnolence, hypoglycemia was found caused by hyperinsulinemia. The Whipple triad during the fasting test confirmed the diagnosis of the hormone producing lesion. The careful non-invasive examinations (abdominal ultrasound, CT and MRI) could not identify the insulinoma. In November 2020 he was admitted to our hospital with severe symptoms of hypoglycemia. Despite the iv. glucose substitution, calcium antagonist and octreotide therapy the hypoglycemia persisted, so calcium stimulation was performed, which showed significant elevation of C-peptide and insulin levels of the middle third of the pancreas, but also an elevation could be found in the tail region. Partial pancreatectomy was scheduled, which needed to be postponed because the patient acquired SARS-Covid 19 infection. Later the partial pancreatectomy was performed, and the histology showed nesidioblastosis. The patient was released from the hospital on calcium-antagonist and diazoxide therapy with good clinical response.

Conclusion

The differential diagnosis of insulinoma and diffuse nesidioblastosis from the clinical and biochemical perspective is challenging when no imaging technique could localize the lesion, but in the perioperative diagnosis the highly sensitive and specific selective intraarterial calcium stimulation can be helpful. The final diagnosis is based on histopathological findings, which determines the further therapeutic steps. In our case, despite the delays and inconveniences caused by the SARS-Covid 19 pandemic, we could achieve a good clinical response with partial pancreatectomy and chemical suppression.