Paragangliomas (extra-adrenal pheochromocytomas) are rare tumors originating in the autonomic nervous system, whose clinical manifestations are the result of excessive production of catecholamines. The classic triad of palpitations, headache, and diaphoresis associated with hypertension (HT), elevated serum and urine catecholamine levels, and visualization of the mass on imaging tests, enables diagnosis of these tumors, which are mostly benign, and if diagnosed and treated early, are a potentially treatable cause of secondary hypertension. We present the case of a 28-year-old woman, a former smoker, sedentary, with a family history of HT, diabetes and coronary heart disease, and a personal history of episodic headaches, diaphoresis and syncope. HT was diagnosed at the age of 18 and controlled with losartan 50 mg/day up to the age of 28, when she was referred to a specialist for "worsening HT"/suspected secondary HT. The patient had no major alterations on physical examination except casual BP of 140/95 mmHg. On further study, ABPM recording revealed a non-dipper profile, with higher than normal blood pressure values and two blood pressure peaks without associated symptoms. She had elevated plasma catecholamine levels and a hypervascular retroperitoneal mass was visualized on CT and MRI, anterior to the inferior vena cava, measuring about 8 x 5.5 x 4.5 cm, with calcifications and areas of necrosis, confirmed by 123(I-MIBG) scintigraphy and PET scan. The mass was excised by laparotomy and the diagnosis of paraganglioma was confirmed. In postoperative follow-up the patient's blood pressure and catecholamine levels had normalized.