Pheochromocytoma diagnosed pathologically with previous negative serum markers.

Background And Objectives: Patients presenting with adrenal masses require workup with catecholamine or metabolite measurements to rule out pheochromocytoma. There is a select portion of patients with marker negative pheochromocytoma. The aim of this study is to compare patient characteristics and presentations between marker positive and marker negative tumors.

Methods: We performed an IRB-approved retrospective chart review of 88 cases of pheochromocytoma excised at our institution from 1995 to 2013. We considered any abnormal elevation in diagnostic test to be marker-positive.

Results: Seventy-eight cases had laboratory results available. Among these, seven had no elevations in laboratory testing. There was no difference in age or tumor size, but marker-negative patients had higher BMI than marker-positive patients. Marker negative patients were more likely to present with vertigo/dizziness (P = 0.003). Neither was more likely to have a genetic syndrome associated with risk of pheochromocytoma.

Conclusions: Marker-negative pheochromocytoma is uncommon, representing 9% of cases in our series. Of patients with adrenal masses or presentation suggesting catecholamine excess with normal labs, those with vertigo/dizziness may warrant a metaiodobenzylguanidine scan or repeat testing to avoid missing pheochromocytoma. Clinicians may need a high degree of suspicion for pheochromocytoma in patients with negative testing and elevated BMI.