Biochemical and radiological relationships in patients with pheochromocytoma: Lessons from a case control study

Subramanian Kannan, Andrei Purysko, Charles Faiman, Erick M. Remer, Lisa Shah, James Bena, Allan Siperstein, Eren Berber, Amr Fergany, Emmanuel Bravo, Amir H. Hamrahian

Research output: Contribution to journalArticlepeer-review


Background An elevation of fractionated plasma or urinary metanephrine (MN) or nor-metanephrine (NMN), collectively called metanephrines (MN and NMN), >4-fold above the upper limit of normal (ULN) is usually considered to be diagnostic for pheochromocytoma (PHEO). There are a greater number of false positive results when the elevations are more modest. Aim To identify biochemical and radiological features in PHEOs with modest elevations (<4-fold above ULN) of metanephrines. Methodology We retrospectively reviewed the charts of 112 patients with PHEO (10% extra-adrenal) and 208 patients with a non-PHEO adrenal mass operated from 1997-2011, who had metanephrines measured pre-operatively. We divided PHEO into group 1 (n = 90) with metanephrines ≥4-fold ULN and group 2 (n = 22) with metanephrines <4-fold ULN. The non-PHEO group was designated as group 3. Results The median (range) tumour size in group 1 and group 2 was 4·8 cm (1·7-22) and 3·0 cm (1·7-5) respectively (P < 0·001). All patients with PHEO in group 2 had a tumour <5 cm in size. The MN fraction was elevated in about 65% of groups 1 and 2; only 2 (1%) patients in group 3 had an elevated urinary MN fraction, and none were associated with an elevated plasma MN fraction. All PHEOs had a pre-contrast attenuation ≥17 Hounsfield Units (HU). Conclusions Modest elevations (<4-fold ULN) of the NMN fraction in an adrenal mass >5 cm are almost always falsely positive. Elevations in plasma and urinary MN fraction are less likely to be false positive. The CT pre-contrast attenuation of PHEOs is >10 HU.

Original languageEnglish (US)
Pages (from-to)790-796
Number of pages7
JournalClinical Endocrinology
Issue number6
StatePublished - Jun 2014
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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