In a 20 year period, from 1971 through 1991, 105 chromaffin tumours--excluding cervical ones--were operated by the same surgeon: 50 during the first 15 years and 55 during the last 5 years. Pheochromocytomas are defined as intra-adrenal chromaffin tumours, and paragangliomas--or ectopic pheochromocytomas--as of extra-adrenal location. Among those tumours, 30 were malignant (i.e. metastatic) and 75 benign. Among the 30 malignant tumours, 14 were ectopic, 2 occurred in a MEN II A setting and were bilateral, 2 were associated with liver adenoma and liver hemangioma respectively suggesting Von Hippel-Lindau syndrome, and one case was associated with a seemingly sporadic primary hyperparathyroidism. 9 out of those 30 malignancies were not associated with hypertension. Among 75 benign pheochromocytomas or paragangliomas, 10 were ectopic, 7 occurred in a MEN setting (6 type II, 1 type I). 3 patients without evidence of MEN or other neuroectodermal abnormalities presented bilateral pheochromocytoma, either synchronous (2) or metachronous (1). 7 cases occurred in a Von Hippel-Lindau syndrome (3 bilateral) and 4 in a neurofibromatosis setting (1 bilateral). 3 other cases were familial without evidence of MEN (including a case of triple tumour: bilateral and ectopic and another ectopic case). 2 other cases were associated with seemingly sporadic hyperparathyroidism. As a whole, in 34 of 75 benign pheochromocytomas or paragangliomas, the tumour was not intra-adrenal, unilateral and sporadic. Among those 75 tumours, 22 were not overtly hypertensive, including 10 out of the 41 seemingly intra-adrenal, solitary and sporadic. The pheochromocytoma, benign, intra-adrenal sporadic, hypertensive accounts for no more than 30% of the subphrenic catecholamine-secretin chromaffin tumours.(ABSTRACT TRUNCATED AT 250 WORDS)