Endocrine Abstracts

Background: Although in most cases insulinomas are small and benign tumors, in about 4% they are malignant, mainly in course of inherited syndromes like MEN1, tubular sclerosis or neurofibromatosis type 1. While in case of benign tumors surgery is usually curative, the metastatic form brings difficulties in managing due to dissemination and the risk of recurring, life-threating, severe hypoglycemias. To elucidate the clinical differences between sporadic and MEN-1 linked insulinoma we review clinical characteristics and treatment in cohort of patients treated in our centre since implementation of electronic database.

Material: Data was reviewed from patients diagnosed with insulinoma managed at our centre from 2015 to 2021 year.

Results: There were 19 cases of insulinomas (9 women and 10 men). In 6 (32%) cases the mutation in menin gene were confirmed. The median age at diagnosis in the whole group was 58 years, (range 16-87 years) in case of sporadic and MEN-1 related insulinoma 69 years (range 29-87 years) and 40 years (range 6-79 years) respectively. In case of MEN-1 related insulinoma at diagnosis 5/6 patients had primary hyperparathyroidism (PHP) in one case it was confirmed 11 years after insulinoma diagnosis. None of patients with negative MEN-1 gene mutations had PHP, 2 out of 13(13%) had dissemination of insulinoma at diagnosis. Median of Ki67 in case of sporadic insulinoma was 2% range (1-12%) and in case of MEN-1 related insulinoma 2% range (1-5%). In 3 cases (50%) of MEN-1 related insulinoma there was more than one lesion of neuroendocrine characteristic in pancreas. In 6 out of 19 cases (32%) insulinoma was disseminated at diagnosis, in 23% cases (3 out of 13) of sporadic and in 50% (3 out of 6) cases of MEN-1 related insulinoma. All patients with disease limited to pancreas were treated radically by surgery (in 3cases by tumor enucleation, in 8 cases with partial or total pancreatodudenectomy). One of MEN-1 patient had recurrence of hypoglycemia after surgery due to appearance of new insulinoma lesion. The patients with dissemination were treated, due to symptomatic hypoglycemia, with combination of diazoxide, somatostatin analogues and PRRT. 5 out of 6 patients with insulinoma in course of MEN-1 mutation are still alive), one died because of coexisting pancreatic cancer.

Conclusion: There are clinical differences between the course of sporadic and MEN-1-associated insulinoma. In the case of disseminated disease, there is often a need for multi-drug treatment to delay progression and prevent episodes of severe hypoglycemia.