Differences in clinical characteristics, treatment, and outcomes of sporadic and MEN-1-related insulinomas.

Introduction: Although in most cases insulinomas are small, benign, sporadic tumours, they can also be associated with hereditary syndromes, most commonly multiple endocrine neoplasia type 1 (MEN-1). Such a diagnosis significantly affects patient management. The objective was to elucidate the clinical differences between sporadic and MEN-1-linked insulinoma.

Material and methods: Comparison of clinical and histopathological characteristics, types of surgery, and outcomes of patients with sporadic and MEN-1-related insulinoma diagnosed between 2015 and 2022.

Results: There were 17 cases of insulinomas that underwent MEN-1 genetic testing (10 women and 7 men). In 7 cases, the mutation in the menin gene was confirmed. The median age at the time of diagnosis of sporadic insulinoma related to MEN-1 was 69 years (range 29-87) and 31.5 years (16-47), respectively. Primary hyperparathyroidism (PHP) was found in 6 of 7 patients with MEN-1-related insulinoma, while in none of the patients without MEN-1 mutations. Multifocal pancreatic NETs were found in 3 patients with MEN-1 syndrome, while in all sporadic cases there was a single pancreatic tumour. Two patients with insulinoma related to MEN-1 had a positive familial history of MEN-1-related diseases, while none with sporadic form. Dissemination at diagnosis was found in 4 cases, including 3 patients with insulinoma related to MEN-1-related insulinoma. Patients with sporadic and MEN-1-related insulinoma did not differ in tumour size, Ki-67 proliferation index, and outcome.

Conclusions: Of all the features evaluated, only the multifocal nature of pancreatic neuroendocrine tumour (PanNET) lesions and a positive family history differentiated between patients with sporadic and MEN-1-related insulinomas. An age of insulinoma diagnosis of less than 30 years may be a strong indicator of an increased risk of MEN-1 syndrome.