What is the most common clinical diagnosis in patients with Multiple Endocrine Neoplasia type 1 (MEN-1)?

Patients with Multiple Endocrine Neoplasia type 1 (MEN-1) most commonly present with parathyroid hyperplasia. MEN-1, also known as Wermer's syndrome, is characterized by a triad of endocrine tumors that commonly include hyperparathyroidism, pituitary tumors, and pancreatic endocrine tumors. Among these, primary hyperparathyroidism due to parathyroid hyperplasia is the most prevalent finding, occurring in approximately 80-100% of patients with MEN-1 during their lifetime.

The parathyroid glands become hyperplastic, leading to elevated levels of parathyroid hormone (PTH), which in turn causes hypercalcemia and its associated complications. This hyperparathyroid state is often the first clinical manifestation of MEN-1, making it critically important both for diagnosis and management.

In contrast, while pituitary adenomas and pancreatic endocrine tumors are also components of MEN-1, they occur with less frequency compared to parathyroid hyperplasia. Medullary thyroid carcinoma, although an important endocrine malignancy, is primarily associated with MEN-2 rather than MEN-1, and does not have the same prevalence in MEN-1 patients.