Insulinoma in a patient with MEN 1 syndrome--9-year follow-up: case report

Multiple endocrine neoplasia type 1 (MEN 1) is a rare autosomal dominant inherited endocrine disease characterized by pancreatic, parathyroid, and anterior pituitary tumours. Hypercalcaemia due to parathyroid tumours is usually the first manifestation of MEN 1. Pancreatic islet tumours occur less frequently, among them gastrinomas and insulinomas are the most prevalent. Prolactinomas are a relatively common pituitary presentation of the syndrome. The gene causing MEN 1 is localized in chromosome 11q13 and encodes a protein named menin, which interacts with various proteins involved in transcriptional regulation, cell division, and DNA repair. Various mutations in the menin gene have been described, but so far no strong correlation between genotype and phenotype has been found.

We report a case of a 31-year-old man, a lawyer, who was diagnosed with MEN 1 syndrome in 1999 at the age of 21 when he was operated because of prolactinoma and hyperparathyroidism. In 2000 insulinoma was suspected and eventually multifocal lesions in the pancreas were revealed. However, the patient did not agree to be operated on. Since then he has been followed up and has been treated with diazoxid. We observed gradual progression of the disease, but the patient remains in relatively good condition.

Careful screening for MEN 1 is important in young patients with pituitary tumours. Regular follow up is crucial even after surgical treatment. The presented patient developed gradual enlargement of insulinomas and reoccurrence of hyperparathyroidism as well.