The patient was a 54-year-old woman who developed a right adrenal tumour, Cushingoid features, elevated levels of cortisol that were not suppressed by 1 nor 8 mg of dexamethasone, and suppression of adrenocorticotropin (ACTH) during treatment for severe hypertension. Computed tomography (CT) revealed a right adrenal tumour and an atrophic left adrenal gland. In addition, elevated plasma aldosterone concentration (PAC) and suppressed plasma renin activity (PRA) with an aldosterone-to-renin ratio of 128 (ng per 100 ml per ng ml⁻¹ h⁻¹) suggested aldosterone excess. Urinary excretion of aldosterone was relatively high, and the captopril and rapid ACTH tests resulted in no response of PRA and exaggerated increase in PAC, respectively. ACTH-loaded adrenal venous sampling showed bilateral excess of aldosterone with right predominance of cortisol. Right laparoscopic partial adrenalectomy (ADX) and immunohistochemical analysis showed both a cortisol-producing adenoma and an aldosterone-producing microadenoma (microAPA) within the attached adrenal, which had not been detected by CT preoperatively. After the right partial ADX, her blood pressure, aldosterone level and suppressed PRA remained unchanged. Subsequently, laparoscopic total left ADX was performed. Two microAPAs with paradoxical hyperplasia were revealed within the apparently atrophic left adrenal gland. Soon after the second surgery, her blood pressure normalized without requiring any anti-hypertensive medication.