Phaechromocytoma is a rare catecholamine secreting tumor, which occasionally presents as a life threatening crisis in association with surgery and anesthesia. We report a 58-year-old women with known Recklinghausen's disease who was admitted for elective resection of a pancreas tail cystadenoma. A cystadenocarcinoma was taken into account differential diagnostically. No clinical symtoms or signs pointing to a hormone active tumor were found preoperatively. After opening of the abdomen and palpation of the tumor, a hypertensive crisis occurred accompanied by considerable tachycardia, leading to the tentative diagnosis of a phaeochromocytoma in connection to the known phacomatosis. The hypertensive crisis was treated with nitroglycerin and esmolol. The putative tumor of the pancreas represented itself as an adrenal tumor without relationship to the pancreas. Following ligature of the suprarenal vein, antihypertensive therapy could be finished. For stabilization of blood pressure a noradrenaline application was necessary in descending dosage over a period of two days. The further postoperative course was without complications. The results of the urine catecholamine measurements and histological examinations confirmed the intraoperative diagnosis. An unidentified phaeochromocytoma is a vital threat for patients during surgery and anesthesia. Phaeochromocytomas are observed in patients suffering from Recklinghausen's disease (and other phacomatoses) in an above average incidence. Therefore, such a tumor should be excluded in these patients before elective surgery even if the patient does not show symptoms (asymptomatic phaeochromocytomas occur). The determination of catecholamines in 24 hour urine collections is an easy and specific diagnostic procedure and should be used in patients suffering from phacomatoses before elective surgery.