Clinical and Pathological Characteristics of Hypertensive and Normotensive Adrenal Pheochromocytomas

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.

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.

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).

HPs and NPs have distinct differences in clinical, biochemical and pathological phenotypes, which are closely related with productions involved in tumor occurrence and development.