One of the rare causes of flash pulmonary edema is pheochromocytoma. This is a catecholamine-producing neuroendocrine tumor arising from chromaffin cells of the adrenal medulla (80 to 85%) or extra-adrenal paraganglia (15 to 20%) The clinical presentation is highly variable, but the classic pentade of symptoms consists of pain, perspiration, palpitations, pallor, and high BP. Other symptoms include acute heart failure, orthostatic hypotension, polyuria, polydipsia, anxiety or panic attack, hyperglycemia, lactate acidosis, and weight loss. These symptoms are caused by the release of norepinephrine, epinephrine, and dopamine, which can be measured in a 24-h urine sample. This is diagnostic in > 95% of symptomatic patients. Acute episodes of pheochromocytoma may be difficult to diagnose and give normal values because of the transient rise in catecholamine levels in the urine. Chromogranin levels are elevated in 80% of cases. Identification of a mass can be achieved by use of 123I-metaiodobenzylguanidine (MIBG) scanning. MIBG is a compound resembling norepinephrine that is taken up by adrenergic tissue.