[Pheochromocytoma associated with multiple endocrine neoplasia 2A and sporadic: differential characteristics]

To study distinctive clinical features of pheochromocytoma in the setting of multiple endocrine neoplasia type 2A (MEN 2A) in comparison with sporadic pheochromocytoma.

All patients diagnosed of sporadic pheochromocytoma (n = 29) and in the setting of MEN 2A (n = 16) between 1976 and 1998 in a tertiary hospital were included in the study. The following variables were compared: age at diagnosis, symptoms, presence and characteristics of hypertension, size of the tumor, localization and malignancy. The accuracy of diagnostic tests was also evaluated.

The pheochromocytoma associated to MEN 2A had a higher prevalence in our study (35.5%) and the diagnosis was performed earlier than for sporadic pheochromocytoma (29.1 [7.8] vs. 47,5 [10. 9] years; p < 0.001). Other distinctive features in comparison with sporadic pheochromocytoma were: bilaterality (81.25 vs. 3.44%; p < 0. 001), absence of symptoms (44 vs 11%; p < 0.05) and paroxysmal hypertension. Concerning the diagnostic tests, it must be noted the low sensitivity (60%) of vanillylmandelic acid in MEN 2A.

The pheochromocytoma in the setting of MEN 2A is diagnosed at younger age and frequently asymptomatic and bilateral. In view of the high prevalence of MEN 2A in our country, a genetic analysis should be performed in all patients with pheochromocytoma, especially when it is bilateral.