Clinical outcome of 50 patients with malignant abdominal paragangliomas and malignant pheochromocytomas

Background: Tumors of the paraganglionic system represent a distinct, albeit uncommon, clinical entity characterized by catecholamine hypersecretion and hemodynamic instability; initial pathologic examination often cannot predict benign vs malignant behavior. An analysis of the clinical outcome of patients with known malignant tumors may serve to enhance the initial evaluation and therapeutic plan of all patients presenting with pheochromocytoma or paraganglioma. Methods: At the University of Texas M D Anderson Cancer Center, 30 patients with malignant abdominal paraganglioma and 20 patients with malignant pheochromocytoma were diagnosed between 1971 and 1995. Their medical records were reviewed with particular attention to clinical characteristics and disease outcome. Results: Among the 30 patients with paraganglioma, 73% were men, and 90% were younger than 50 years at the time of diagnosis. Sixteen patients have remained alive with persistent disease 0.2 to 25 years after initial diagnosis while eight patients died of their disease within 0.8 to 32 years. Regional recurrence and skeletal metastases were the most prominent events. Among the 20 patients with pheochromocytoma, 60% were men and 70% were younger than 50 years at the time of diagnosis. Ten patients have remained alive with persistent disease 0.8 to 20 years after initial diagnosis while five patients died of their disease within 1.5 to 39 years. Hypertension was a prominent presenting feature and regional recurrence was the most frequent pattern of treatment failure. Conclusions: Important clinical differences distinguish adrenal pheochromocytomas from extraadrenal, abdominal paragangliomas. Patients with paragangliomas are, as a group, younger men, more likely to have malignant lesions and a more aggressive clinical course. Patients with malignant pheochromocytomas usually present with hypertension, are somewhat older, and have less aggresEndocrine-Related Cancer (1998) 5 59-68 sive disease. Vassilopoulou-Sellin: Malignant abdominal paragangliomas and pheochromocytomas 60 benign and malignant lesions (Oishi & Sato 1988, Helman et al. 1989, Nativ et al. 1992, Montressor et al. 1994). Because metastases may not develop until more than 10 years have passed since the diagnosis, it is not possible to distinguish truly benign lesions without a very prolonged observation period for all reported cases. Lack of agreement exists as to the virulence and malignant potential of paragangliomas relative to pheochromocytomas (Lack et al. 1980, Scott & Halter 1984, Shapiro et al. 1984) and other distinguishing characteristics. It has been our clinical impression that abdominal, extra-adrenal paragangliomas and adrenal pheochromocytomas are distinct clinical entities. Among these lesions, paragangliomas most often afflict young males and are more likely to be malignant and aggressive. Accordingly, we analyzed the clinical outcome of patients with paragangliomas and pheochromocytomas who were treated at the M D Anderson Cancer Center. Our aim was to distill individual characteristics of malignant, abdominal paraganglioma as distinct from malignant adrenal pheochromocytoma. Patients and methods