Letter to the Editor Hormone Research Horm Res 1997;48:135-136 Michael Stumvoll a Andreas Pritsche3 Andreas Pickertb Dietrich Overkampa Features of Malignancy in a Benign Pheochromocytoma Medizinische Universitätsklinik. Tiibingcn. und Städtisches Klinikum, Heilbronn, Deutschland Pheochromocytomas are rare conditions with a prevalence of 1-2/100,000 in the gen eral population and 1/1,000 hypertensive subjects [ 1 ]. 10% of pheochromocytomas arc malignant and various attempts have been made to find useful prognostic indicators of malignancy. In general, increased plasma or urine dopamine concentrations or increased homovanillic acid excretion and lack of 131- methyliodo-benzylguanidinc uptake have been associated with malignancy [2], How ever, to date no specific metabolic, radio- logic or histopathologic features of either be nign or malignant pheochromocytomas al lowing the safe diagnosis of one or the other have been identified. The diagnosis of malig nant pheochromocytoma can be made only in the presence of local tissue invasion or distant métastasés. We present a benign pheochromocytoma exhibiting several fea tures suggestive of malignant disease. A 20-year-o!d patient was referred to hos pital with a 2-year history of paroxysmal pal pitations most recently accompanied by se vere headache and flushing. Latest blood pressure readings were persistently above 200 mm Hg systolic and 120 mm Hg diastol ic. In addition, an increased dislike of sweets together with exaggerated salt-hunger was re ported. Except for hypertension the physical examination was unrevealing. Abdominal ultrasound showed a left adrenal mass which was confirmed by CT scan but undetectable by methyliodo-benzylguanidine scanning. Laboratory investigations performed in the appropriate manner revealed 10-fold ele vated plasma and urinary' norepinephrine concentrations and 3- to 4-fold elevated plas ma and urine dopamine levels as shown in table 1. Neuron-specific enolase was at the upper limit of normal (12.9 pg/1). Resting scrum aldosterone of 459 pg/ml (normal range <160) and plasma renin activity of 7.98 ng/ml/h (normal range < 1.6) were in creased, while prolactin, growth hormone, thyroid function tests, calcitonin, adrenocor- ticotropin and cortisol were all normal. The patient underwent left adrenalecto my and thorough abdominal exploration. With the adrenal capsule intact no signs of local tissue invasion by the tumor were de tected. Microscopy confirmed the diagnosis of pheochromocytoma but showed neither angioinvasive nor capsule penetration. Post- operatively, blood pressure and catechol amine levels returned to normal. During the follow-up period of 55 months, the patient has led a normal life without clinical symp toms of pheochromocytoma or elevated urine or plasma catecholamines (table 1). The intraoperative findings and the his tology report in conjunction with a 5-year follow-up without recurrence of symptoms or abnormal catecholamines allowed us to establish the diagnosis of a benign pheochro mocytoma in this patient. Preopcratively, however, several findings were indicative of malignant pheochromocytoma. Young age at presentation has generally been associated with an increased likelihood of malignancy [3], Futhermore, although norepinephrine was the predominantly ele- KARGER E-Mail karger(fl!karger.ch F a x + 41 61 306 12 34 http://www. kargcr.ch © 1997 S. Karger AG. Basel 0301 -0163/97/0483-0135S12.00/0 This article is also accessible online at: http://BioMedNet.com/karger Dr. Michael Stumvoll Medizinische Universitätsklinik Otfried-Müller-Strasse 10 D-72076 Tübingen (Germany) Tel. (7071) 2982711. Fax (7071 ) 298278<i