In MEN2A, what two additional endocrinopathies co-occur with medullary thyroid carcinoma?

• A. Pheochromocytoma and primary hyperparathyroidism
• B. Graves disease and Addison disease
• C. Cushing syndrome and hypoparathyroidism
• D. Hashimoto thyroiditis and diabetes mellitus type 1

Answer: (A)

In MEN2A, medullary thyroid carcinoma sits alongside two other endocrine tumors: pheochromocytoma and primary hyperparathyroidism. Pheochromocytomas are adrenal tumors that secrete excess catecholamines, which can cause headaches, sweating, palpitations, and high blood pressure; identifying them is crucial before any thyroid surgery to avoid dangerous catecholamine surges during manipulation. Primary hyperparathyroidism results from parathyroid overactivity, leading to elevated calcium levels. These three findings—medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism—define the MEN2A pattern. Other autoimmune or metabolic conditions listed do not form part of this syndrome.