Endocrine Abstracts

JOINT2427

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder characterized by synchronous or metachronous neuroendocrine tumors. The three main clinical features of this disease are primary hyperparathyroidism (pHPT), duodenal-pancreatic neuroendocrine tumors, and anterior pituitary tumors (1,2). pHPT is the most common and often the first clinical manifestation in 90% of cases (3). We report a rare case of MEN1 in which a pituitary adenoma appeared before pHPT, emphasizing the need to consider other early manifestations of the disease.

Case Report: A 57-year-old female with a history of bilateral cystic mastopathy and LADA (Latent Autoimmune Diabetes in Adults), developed a 5 mm microprolactinoma at age 27. The adenoma was managed with transsphenoidal surgery, complicated by corticotropic insufficiency, which was corrected with hydrocortisone replacement. At age 51, 24 years after the pituitary adenoma, pHPT was diagnosed late, following the development of renal (kidney stones) and bone (recurrent fractures) complications. Histopathological examination confirmed a parathyroid adenoma. MEN1 screening did not reveal any additional components beyond the two already identified.

Discussion & Conclusion: MEN1 is an uncommon condition, with an estimated prevalence of 3 to 20 cases per 100,000 individuals (1). In this disorder, pHPT is the first clinical manifestation in 90% of cases (3). However, although less frequent, a pituitary adenoma can also present as the first expression of the disease (4). It is estimated that about 30-40% of MEN1 patients develop pituitary adenomas during the course of the disease. Among these, approximately two-thirds are classified as microadenomas, with prolactinomas predominating in 65% of cases (3). This case highlights the importance of considering pituitary adenoma as an early manifestation of MEN1, without necessarily expecting pHPT to appear first.

References: 1. Manoharan, J., Albers, M. B., Rinke, A., Adelmeyer, J., Görlach, J., & Bartsch, D. K. (2024). Multiple Endocrine Neoplasia Type 1: The Current Status of Disease Management. Deutsches Ärzteblatt International, 121(9), 527–533. https://doi.org/10.3238/arztebl.2024.0527 2. Marinari, M., Marini, F., Giusti, F., & Brandi, M. L. (2024). Role of nutrition in the management of patients with multiple endocrine neoplasia type 1. Nutrients, 16(11), 1576. https://doi.org/10.3390/nu16111576 3. Ramamoorthy, B., & Nilubol, N. (2023). MEN1 PNET Genotype/Phenotype – Is there any advance on predicting or preventing? Surgical Oncology Clinics of North America, 32(2), 315–325. https://doi.org/10.1016/j.soc.2022.10.008 4. Barlier, A., Romanet, P., & Pellegata, N. S. (2023). Editorial: New insights into multiple endocrine neoplasia type 1. Frontiers in Endocrinology, 11, Article 1266148. https://doi.org/10.3389/fendo.2023.1266148