Cervical paragangliomas: is SDH genetic analysis systematically required?

To evaluate the prevalence of succinate dehydrogenase (SDH) B, C, and D germline mutations in a surgical series of cervical paragangliomas and to precise the characteristics of patients presenting with familial form. Among 29 patients operated on cervical paragangliomas (carotid or vagal body) at our institution between 1994 and 2007, 23 could be asked for a genetic analysis and a familial study. Clinical characteristics of patients harboring a germline SDH mutation were studied and compared with those presenting without mutation. Mutations were found in 8/23 (35%) patients, mostly in SDHD gene (6 cases), and in SDHB and SDHC gene, respectively, in one case each. Mean age at onset was significantly lower for patients with mutation (34 vs. 51.5 years, P = 0.01). In patients presenting with a mutation, 50% had a family history of paraganglioma compared with 0% for others (P = 0.008) and 87.5% had a multifocal form of paragangliomas versus 0% for others (P = 0.001). No difference was found concerning malignant forms between the two groups (12.5 vs. 13.3%). In the 16 patients who had an apparently sporadic paraganglioma, 6% had mutations in the SDH gene. A positive family history of paraganglioma and/or the presence of bilateral or multiple paragangliomas and/or an early age of onset are the main parameters associated with SDH mutations. Genetic testing should be considered for all patients with a cervical paraganglioma, even for those presenting with an apparently sporadic tumor as familial form may be such identified in 6% of cases.