A case is reported of a phaeochromocytoma revealed during a general anaesthesia by a sudden hypertensive crisis associated with acute pulmonary oedema and signs of extreme sympathetic stimulation (bilateral mydriasis, piloerection, peripheral vasoconstriction). Aortic angiography revealed the tumour lying in an ectopic retroperitoneal situation and spasm in the superior mesenteric arterial territory. The patient died at the thirtieth hour from septic shock due to necrotizing colitis.