Introduction: Multiple endocrine neoplasia type IIa (MEN IIa) is an autosomal dominant syndrome characterized bypheochromocytoma ,medullary thyroid carcinoma and hyperparathyroidism. Pheochromocytoma approximately occurs in 50% of patients with MEN IIa. This tumor has the capacity to produce ACTH ectopically and becomes manifest like Cushing syndrome,although it is very rare. Case Report: We report a 26-year-old woman patient with severe muscle weakness, skin lesions in extremity, hypertension, new onset diabetes and in the laboratory data hypokalemia, metabolic alkalosis, high serum level of cortisol, metanephrine, normetanephrine, calcitonin and bilateral adrenal mass in computed tomography as the first clinical manifestations of an ACTH-secreting pheochromocytoma.

Conclusion: In the patients with hypertension, new onset diabetes and hypokalemia Cushing syndrome and pheochromocytoma should always be ruled out.