Diagnosis of MEN 2B Serum calcitonin levels Plasma free metanephrines and urinary catecholamine levels Neck CT or MRI Pheochromocytoma localization with magnetic resonance imaging (MRI) or computed tomography (CT) Genetic testing MEN 2B is suspected in patients with a family history of MEN 2B, pheochromocytoma, multiple mucosal neuromas, or medullary thyroid carcinoma.