Diagnosis of pheochromocytoma in the setting of Parkinson disease

• Published in: Nature reviews. Neurology Vol. 5; no. 6; pp. 343 - 347
• Main Authors: Mehta, Shyamal H, Prakash, Rajan, Prisant, L. Michael, Isales, Carlos M, Morgan, John C, Williams, Hadyn, Sethi, Kapil D
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-06-2009; Nature Publishing Group
• Subjects: 3-Iodobenzylguanidine; Abdomen; Accreditation; Adrenal Gland Neoplasms - complications; Adrenal Gland Neoplasms - diagnostic imaging; Adrenal glands; Blood pressure; Bone surgery; Cardiac arrhythmia; Care and treatment; Case studies; case-study; Catecholamines - metabolism; Complications and side effects; Diagnosis; Heart rate; Humans; Hyperplasia; Hypertension; Laboratories; Magnetic Resonance Imaging - methods; Male; Medical education; Medicine; Medicine & Public Health; Middle Aged; Movement disorders; Neck pain; Neurology; Parkinson Disease - complications; Parkinson's disease; Patients; Pheochromocytoma; Pheochromocytoma - complications; Pheochromocytoma - diagnostic imaging; Risk factors; Tomography, Emission-Computed, Single-Photon - methods; United States; United States > US
• ISSN: 1759-4758; 1759-4766
• DOI: 10.1038/nrneurol.2009.55

The neuroendocrine tumor pheochromocytoma is usually detected via measurement of levels of catecholamines and their metabolites in plasma and urine. In patients with Parkinson disease, however, the results of these tests can be confounded by dopaminergic medications. Mehta
et al
. present the case of a 59-year-old man with Parkinson disease in whom a diagnosis of pheochromocytoma was confirmed by means of structural and functional imaging.
Background
. A 59-year-old man with a 7-year history of Parkinson disease (PD) presented with episodes of sudden, severe headaches with neck pain, tachycardia, sweating and pallor. During these episodes, the patient showed marked elevations in blood pressure, regardless of posture. This was unusual, given that he had no prior history of hypertension. The array of symptoms raised suspicions of pheochromocytoma, but diagnosis was challenging, as the standard diagnostic biochemical tests were confounded by dopaminergic medications. Further work-up revealed left adrenal medullary hyperplasia. Several reports exist of pseudopheochromocytoma in patients on dopaminergic therapy, but this is the first documented case of pheochromocytoma syndrome due to adrenal medullary hyperplasia in a patient with PD. This case highlights the challenges of performing a diagnostic work-up in a PD patient with symptoms suggestive of pheochromocytoma, and illustrates the utility of
123
I-metaiodobenzylguanidine (
123
I-MIBG) single-photon emission CT in making a diagnosis.
Investigations
. Physical examination, laboratory tests, abdominal MRI scan, abdominal
123
I-MIBG scan, abdominal
18
F-fluorodeoxyglucose PET scan.
Diagnosis
. Pheochromocytoma syndrome due to adrenal medullary hyperplasia.
Management
. Surgical excision of the left adrenal gland.