Introduction: Mutations in the succinate dehydrogenase gene (SDH) predispose to the development of paraganglioma (PGL) which arise from parasympathetic and extra-adrenal sympathetic-associated chromaffin tissues. Identification of an index case results in family cascade screening, often of asymptomatic individuals.
Aims: To identify prevalence of PGL tumours and elevated plasma metanephrines at first screening in patients newly identified as carrying a pathogenic SDH mutation.
Methods: Data collection from a database of patients with SDH mutations at Guys and St. Thomass NHS Foundation Trust. Following confirmation of a pathogenic SDH mutation all patients had measurement of plasma metanephrines and whole-body (incl. head & neck) MRI.
Results: 35 adult patients (mean age 39 years; range 1066) were included. All were asymptomatic and identified as carrying a mutation in SDH through family screening (3 with SDHA, 24 with SDHB, 3 with SDHC and 5 with SDHD). Using MDM records initial biochemical and cross-sectional screening results were obtained. 10 of 35 patients (29%, 5 with SDHB mutation and 5 with SDHD mutation) had a tumour at initial screening. Tumour locations were as follows; 4 head and neck (3×SDHD, 1×SDHB), 5 abdominal (2×SDHD, 3×SDHB) and 1 thoracic (SDHB). 4 patients had elevated metanephrines at initial screening (11%), one of whom had a malignant tumour detected 6 months from initial screen in the thorax (SDHB mutation).
Conclusion: The tumour burden is high (29%) in these adult patients with SDH mutations at initial screening. Tumours were located in the head & neck, abdomen and mediastinum. Not all abdominal tumours were associated with demonstrable catecholamine excess.