Pheochromocytomas are rare catecholamine-producing tumours that arise from the adrenal medulla. They can manifest with paroxysmal hypertension, headache, palpitations, and sweating. Advanced imaging modalities are key for accurate localization. The case is presented of a 66-year-old male admitted in 2018 and diagnosed with a retroperitoneal pheochromocytoma, due to poor physical activity tolerance and resistant hypertension. Abdominal ultrasonography revealed an cystic lesion beneath the right adrenal gland. Hormonal evaluation confirmed elevated plasma methoxy-catecholamines. Due to the unusual location of the tumour, multiple CT scans were required to confirm the diagnosis. The patient underwent pre-operative alpha-blockade therapy to manage catecholamine secretion, followed by successful surgical resection. Retroperitoneal pheochromocytomas are exceptionally rare and diagnostically challenging. Complete imaging and biochemical evaluation are essential for accurate diagnosis.