A Rare Case of Adrenal Carcinoma With Isolated Hypercortisolism Mimicking Hyperaldosteronism

We report a case of a 22-year-old female with pedal edema, hypokalemia, and hypertension. On suspicion of hyperaldosteronism, further workup was pursued, which only revealed a low serum adrenocorticotropic hormone (ACTH) and an inappropriately normal cortisol level after a 1-mg dexamethasone suppression test, suggestive of primary hypercortisolism. CT of the chest, abdomen, and pelvis revealed a left adrenal mass. Based on the clinical findings and biochemical abnormalities, we were expecting this tumor to be aldosterone-secreting, but both serum aldosterone and renin levels were normal in our patient. Eventual surgical resection confirmed initial suspicions of malignancy, as it was found to be adrenal cortical carcinoma. This case highlights the unusual presentation of this rare but aggressive endocrinologic neoplasm and the importance of its prompt diagnosis and treatment.