Karel Pacak: Anatomic imaging studies, either CT or MRI, are used for the initial attempts to locate a PPGL.
Maher: Our standard screening modality to detect PPGL in individuals at increased genetic risk is MRI scanning.
If a PPGL is not detected with this study, the clinician should reassess the diagnosis.
Thus, until there is a reliable method for predicting malignancy, no PPGL should ever be classified as benign.
Maher: In the absence of distant metastases, the presence of a germline SDHB mutation significantly increases the prior risk of malignancy but cannot definitively inform whether an individual PPGL is malignant or not.
The diagnosis of malignant PPGL requires finding this tumor in sites that do not normally contain chromaffin tissues (e.
The study involved retrospective analysis of data from 173 patients with hereditary PPGLs.
Mutations were confirmed by genetic testing in all patients with MEN 2, VHL syndrome, and hereditary PPGLs due to mutations of SDHD and SDHB genes.
Tumor tissue contents of catecholamines varied considerably among the different groups of patients with PPGLs (Fig.
Considered alone, plasma concentrations of normetanephrine and norepinephrine showed no obvious distinguishing differences among the 5 groups of patients with hereditary PPGLs (Fig.
The results of this study establish that measurements of the O-methylated metabolites of catecholamines, in addition to providing useful diagnostic biomarkers for PPGLs, also enable discrimination of different hereditary forms of these tumors.
Increases in plasma concentrations of metanephrine due to pheochromocytomas in patients with MEN 2 and lack of increases in patients with VHL syndrome are established findings (15,27), but it has not been clear whether other hereditary PPGLs are characterized by similarly distinct differences.