High incidence of malignant pheochromocytoma in a surgical unit. 26 cases out of 100 patients operated from 1971 to 1991.

In this surgical series of 100 pheochromocytomas (PH), where 91 cases were studied and followed up, the frequency of malignancy appears high (29%) on macroscopic criteria observed at the first operation (25 out 26 cases of malignant PH) or thanks to the occurrence of metastases (1 case out of 26 malignant PH). While some clinical signs are suggestive, there is no excretory profile predictive of malignancy. Isolated or predominant secretion of dopamine is not specific of malignancy event if it occurs more frequently and severely in malignant PH. Bilateral involvement, occurring in the setting of phacomatosis or of multiple endocrine neoplasia (MEN II), or in a sporadic case, is not a predictor for malignancy. Contrarily, extraadrenal involvement is a major feature indicative of malignancy. A CT scan which demonstrates possible locoregional invasion, and a MIGB scan revealing distant localizations raise the suspicion of malignancy. The preferred surgical approach is via a laparotomy, thus allowing the exploration of all possible abdominal chromaffin site and the search for intraabdominal metastases. Intraoperative MIBG scanning checks the completeness of the excision. Flow cytometric DNA ploidy studies have been performed in 25 of our patients. The follow up of benign or malignant PH, after excision "for cure" must be life-long: clinically, biologically and by MIGB scan. Persistence of the disease after surgery or recurrence with unresectable metastases can benefit from MIGB and chemotherapy.