Acromegaly as the Initial Presentation of Multiple Endocrine Neoplasia Type 1: A Case Report

BACKGROUND Multiple endocrine neoplasia syndrome type 1 (MEN-1) is a rare autosomal-dominant disorder, caused by MEN-1 gene mutations, leading to tumors in multiple endocrine organs, classically the parathyroid glands, the anterior pituitary, and the pancreatic islet cells. Although primary hyperparathyroidism is usually the earliest manifestation, growth hormone-secreting pituitary adenomas rarely present as the initial clinical feature, potentially delaying recognition of the syndrome. CASE REPORT A 34-year-old woman presented with acromegalic features and hypercalcemia. Laboratory testing and magnetic resonance imaging confirmed a recurrent growth hormone-secreting pituitary macroadenoma, and neck imaging identified a parathyroid adenoma. Genetic analysis demonstrated a rare pathogenic variant. After she underwent repeat transsphenoidal surgery, growth hormone and insulin-like growth factor-1 normalized following complete radiological tumor resection. Parathyroid surgery was planned, and the patient was enrolled in multidisciplinary MEN-1 surveillance. CONCLUSIONS The coexistence of a pituitary adenoma and hypercalcemia should prompt evaluation for MEN-1, even in the absence of a family history of the disorder. Early clinical suspicion and recognition enable timely surgical management and structured long-term surveillance, reducing the risk of delayed diagnosis and complications of additional MEN-1-associated tumors. Although MEN-1-associated pituitary adenomas are managed according to the same principles as sporadic tumors, affected patients benefit from multidisciplinary care and lifelong follow-up. Furthermore, reporting rare pathogenic MEN-1 variants contributes to the expanding understanding of genotype-phenotype correlations and the clinical spectrum of this hereditary syndrome. This case highlights that acromegaly may, rarely, represent the first clinical manifestation of MEN-1.