Background: A 52-year-old woman was admitted to hospital with recurrent episodes of chest and abdominal pain, dyspnea, palpitations and diaphoresis. Continuous blood pressure recordings revealed rhythmic alternation between episodes of severe hypertension and episodes of hypotension. This cyclic hemodynamic crisis continued for 2 hours, with each cycle lasting around 15 min. Investigations: Physical examination, electrocardiography, chest radiography, continuous intra-arterial pressure monitoring, blood and urine analysis, echocardiography, abdominal CT and 131I miodobenzylguanidine scanning. Diagnosis: Pheochromocytoma - a catecholamine secreting tumor. Management: Intravenous phentolamine and fluids, oral doxazosin and surgical removal of the tumor.