Background. Pheochromocytoma, the great masquerader, can have a varied spectrum of clinical manifestations. It can often cause a diagnostic challenge despite the availability of modern investigation modalities. Case. We present the case of a 38-year-old male who presented with uncontrolled hypertension for the past 10 years and heart failure for one year. The diagnosis of pheochromocytoma was missed in the initial setting, leading to a biopsy of the retroperitoneal mass. Fortunately, the patient survived the procedure. Subsequently, with the involvement of a multi-disciplinary team, he was optimized for surgery under strict cardiac monitoring. After the complete excision of the tumour, he showed significant improvement not only in his clinical symptoms but also in his cardiac status. Conclusions. This case emphasizes the age-old medical phrase of ‘Primum non nocere or first, do no harm’. Any invasive procedure in a pheochromocytoma can lead to a massive release of catecholamines causing a hypertensive crisis, pulmonary oedema, and even cardiac arrest. Any young patient presenting with hypertension or heart failure should be investigated for secondary causes. Cardiomyopathy due to pheochromocytoma is because of catecholamine overload and usually reverses or improves after curative surgery. © 2024 Elsevier B.V., All rights reserved.