A Malignant Metastatic Insulinoma as the First Clinical Presentation of Multiple Endocrine Neoplasia Type 1: A Case Report

Aim: We report the case of a patient who had a malignant insulinoma as the first presentation of Multiple Endocrine Neoplasia type 1 (MEN1).

Case Presentation: A 54-year-old male patient has reported palpitations, tremor, weight loss (approximately 20 kg) and seizures for one year. A blood sample taken during a fasting hypoglycemic episode revealed a low plasma glucose (35 mg/dL), an elevated immune reactivity insulin (> 300 mUI/ml) and a high C-peptide concentration (7 ng/mL, normal range 1,1 to 4,4 ng/ml). A computed tomography scan of abdomen detected a pancreatic tail tumor of 4 cm. The patient underwent pancreatic surgery and hepatic biopsy that revealed malignant insulinoma with lymphnode and liver metastases. The screening for MEN1 showed an adrenal and pituitary adenoma clinically nonfunctioning. After obtaining informed consent from the patient, mutational analysis of MEN1 gene was performed using genomic DNA isolated from peripheral blood leukocytes. The sequencing analysis showed a heterozygous intronic mutation in intron 3, IVS3-6 C>T. Her daughter and son were evaluated for the IVS3-6 C>T mutation and only the daughter presented the alteration.

Conclusion: We report an uncommon case whose early diagnosis of MEN1 allowed the genetic study, and consequently helped the genetic counseling and early diagnosis of the affected relatives.