[Review of Multiple Endocrine Neoplasia Type 1 Based on a Clinical Case].

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disease with an estimated prevalence of 2 per 100,000. This disease is caused by a mutation in the tumor suppressor gene MEN1, which is located on chromosome 11 and codifies the menin protein. It is characterized by a predisposition of parathyroids, enteropancreatic, and anterior pituitary tumors, affecting the quality of life and lifespan of those who have the disease. Clinical case: We present a case of a 24-year-old woman with recurrent episodes of symptomatic hypoglycemia and first-degree relatives who were diagnosed with insulinoma. Initial studies showed endogenous hyperinsulinism secondary to two pancreatic tumors, the main one measured 8.2 × 4.2 cm, and PTH-dependent hypercalcemia secondary to a parathyroid adenoma. Further studies, based on magnetic resonance imaging of the pituitary, showed a macroadenoma. Additionally, we performed a genetic study that evidenced a deletion in the IAT gene, which is compatible with MEN1 syndrome. Pancreatic and parathyroid surgery were performed, and function substitution therapies were initiated. Discussion: The diagnosis is established in the presence of two or more defining NEM1 tumors or at least one associated with compatible genetic testing or a first-degree relative with a history of MEN1. Screening and surveillance in patients with confirmed MEN1 diagnosis would enable the reduction of the disease burden, with a nonclear impact on lifespan.