Abstract
Introduction: Pheochromocytoma/Paraganglioma (PPGL) present with an extremely variable clinical
picture which ranges from dramatic, to mild, to silent, depending on tumor attitude
to release catecholamines. Hypertension is the hallmark of these tumors but is not
always present. Distinct differences of clinical manifestations exist in hypertensive
pheochromocytomas (HPs) and normotensive pheochromocytomas (NPs), however the comparative
analysis is lacking.
Methods: The objective was to assess the clinical symptoms, hemodynamics, metabolism, radiological
and histological features of patients with HPs and NPs. This study included 104 pheochromocytoma
patients who were categorized into HPs (n=69) and NPs (n=35) groups. All clinical
records were reviewed. Tumor samples were examined to determine the Adrenal Gland
Scale Score and were available for measurement of gene transcriptions. Biochemical
examinations of 95 subjects with primary hypertension (PH) were recorded for comparative
study.
Results: Patients with NPs showed lower proportion of clinical triad, inapparent metabolic
disorders and lower urinary catecholamine levels than HPs, but higher than PH. Tumor
weight positively correlated with 24 h urinary norepinephrine level in patients with
HPs (P=0.028), and tumor diameter negatively correlated with phenylethanolamine-N-methyltransferase
(PNMT) immunohistochemistry (P=0.011) in NPs but not in HPs. The Adrenal Gland Scale
Score of NPs group was similar to that of HPs group. The positive percentage of epinephrine
type (E-type) of catecholamine in HPs group was higher than that in the NPs. The transcript
gene levels of PNMT, secretogranin II (SGII) and neuropeptide Y (NPY) from tissue
samples were significantly lower in NPs than in HPs (PPNMT=0.038, PSGII=0.040, PNPY=0.032), while vesicular monoamine transporter 1 (VMAT1) had no difference between
HPs and NPs (PVMAT1=0.053).
Conclusion: HPs and NPs have distinct differences in clinical, biochemical and pathological phenotypes,
which are closely related with productions involved in tumor occurrence and development.
Key words
adrenal medulla - catecholamine - hypertension - metabolism - pheochromocytoma