Pheochromocytoma in Multiple Endocrine Neoplasia Type 2: European Study. The Euromen Study Group

Objectives: Pheochromocytoma (pheo) is the second component of the multiple endocrine neoplasia type 2 (MEN 2) syndrome. Clinical expression is sometimes poor, and chronology between medullary thyroid carcinoma (MTC) and pheo is not well evaluated. Therefore, a retrospective study was done in eight European countries in order to precise the main characteristics of pheo in MEN 2.

Subjects: Data from 300 MEN 2 patients with pheo (274 MEN 2 A and 26 MEN 2 B) were obtained from cases registered by the EuroMen study group, and collected by a medical standardized questionnaire. These cases occurred between 1969 and 1992.

Results: Mean age at diagnosis of pheo was 39.5 years (range 14-68 years) in MEN 2A and 32.4 years (range 15-41 years) in MEN 2B patients. Pheo occurred first in 25.1% of the cases (2-15 years before diagnosis of MTC) and after MTC in 40.2% (2-11 years). In other cases (34.7%), MTC and pheo were diagnosed at the same time. Involvement was bilateral in 67.8% of cases. Malignancy was only 4%. Thirty-nine deaths occurred in these 300 patients, 64.1% were linked in pheo, 23.1% to MTC and 12.8% to other causes. Surgery was unilateral in 39.7% of the cases and bilateral adrenalectomy was the first procedure in 48.4%. A bilateral adrenalectomy in two steps had to be done in 11.9% of cases. In conclusion, these results justify systematic and prolonged biochemical screening of pheo during follow-up of MTC and address some questions about the best mode of surgery.