Pheochromocytoma in Neurofibromatosis Type 1: When Should it Be Suspected?

Abstract

Objective: Neurofibromatosis type 1 (NF1) carries an increased risk of pheochromocytoma. Most experts recommend that NF1 patients be screened for pheochromocytoma if hypertension develops. We sought to compare NF1 and non-NF1 patients with pheochromocytoma.

Methods: Retrospective analysis of a prospectively collected database of all patients undergoing pheochromocytoma resection by a single surgeon from 2003-2012. Statistical significance was evaluated using Fisher's exact test for categorical variables and the Wilcoxon rank sum test for continuous variables.

Results: Of 56 patients undergoing pheochromocytoma resection, 6 (11%) had NF1. All 6 (100%) NF1 patients had pheochromocytoma diagnosed incidentally during work-up for another condition, whereas 28 of 50 (56%) non-NF1-associated pheochromocytomas were diagnosed incidentally (P = .071). Hypertension was present in 1 (17%) NF1 patient and in 37 (74%) of the non-NF1 patients (P = .011). Tumors were significantly smaller in NF1 patients compared with non-NF1 patients (median tumor dimension, 2.75 cm vs. 5.9 cm, respectively; P = .014).

Conclusion: Although NF1 patients have a well-known increased risk of developing pheochromocytoma, in the current series, all NF1 patients referred to the surgeon for adrenalectomy had pheochromocytoma diagnosed incidentally. Nevertheless, NF1 patients had significantly smaller tumors and less hypertension than other patients treated for pheochromocytoma, perhaps due to a higher frequency of imaging occasioned by their other neoplasms. The common recommendation to screen for pheochromocytoma when hypertension develops would have failed to spur screening in 83% of these NF1 patients. Routine screening for pheochromocytoma in all NF1 patients may be warranted after evaluating whether this is cost-effective in reducing morbidity and mortality.