BACKGROUND Adrenocortical carcinoma (ACC) is a very rare disease, with an incidence of 1.02 per million population per year. The most commonly secreted hormone in ACC is cortisol, often presenting as a rapidly progressive Cushing syndrome (CS). We describe a case of ACC with an unusual presentation, mainly with psychiatric manifestations, including panic attacks and hallucinations. CASE REPORT A 52-year-old woman presented with episodes of acute anxiety, hallucinations, palpitations, hot flashes, gastrointestinal upset associated with paroxysmal hypertension, tachycardia, and flushing for 1 week. The initial workup was aimed at ruling out causes of acute psychosis and/or anxiety such as substance use, and organic diseases such as pheochromocytoma (PCC). Our initial suspicion of PCC was ruled out based on the negative serum and urinary metanephrines (MN) and normetanephrines (NMN). Recurrent metabolic alkalosis and hypokalemia despite fluid and potassium supplementation prompted us to work up for hyperaldosteronism. Her renin level was elevated and the aldosterone level was appropriately suppressed. Elevated cortisol, positive dexamethasone (DXM) suppression test, low adrenocorticotropic hormone (ACTH), imaging revealing an adrenal mass, and postoperative histology confirmed the diagnosis of cortisol-producing ACC. CONCLUSIONS It is essential to recognize psychiatric presentations of CS to achieve early diagnosis and prevent mortality and morbidity. Panic attacks, a common presentation of CS, can present with features mimicking pheochromocytoma (PCC), including palpitations, sweating, tachycardia, and paroxysmal hypertension. A comprehensive workup is warranted to reach a diagnosis, with a combination of hormonal levels, imaging, and histology.