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Malignant pheochromocytoma lacking clinical features of catecholamine excess until the late stage.

A malignant pheochromocytoma is described in a 71-year-old man. Osseous metastases became manifest 12 years after successful removal of the primary tumor which originated in paraganglionic tissue near the right adrenal gland. Although the patient had no symptoms of catecholamine excess initially, hypertension, tachycardia and excessive sweating appeared several months before his death, concomitantly with a sharp increase in noradrenaline secretion due to an accelerated growth of metastatic tumors. Since there is no histologic criterion of malignancy in this neoplasm, it would be prudent to consider every case of pheochromocytoma as potentially malignant and to follow-up carefully for a long time after removal of the primary tumor.