Biochemically Silent Sympathetic Paraganglioma, Pheochromocytoma, or Metastatic Disease in SDHD Mutation Carriers

CONTEXT: Current guidelines do not consistently recommend imaging beyond the head and neck region in succinate dehydrogenase subunit D (SDHD) mutation carriers as long as catecholamine metabolite levels are within the reference range. PARTICIPANTS: We report a series of 10 patients carrying pathogenic variants in the SDHD gene from five tertiary referral centers for paraganglioma (PGL) in the Netherlands, who presented with a sympathetic PGL (sPGL), pheochromocytoma (PHEO), or metastases outside the head and neck region in the absence of excessive catecholamine production. Two of six patients with a biochemically silent sPGL/PHEO developed metastatic disease. Additionally, four patients were found to have metastases outside the head and neck region from head and neck PGL. The average interval between the initial diagnosis and discovery of the silent lesions was 10 (range, 0 to 32) years. CONCLUSIONS: The absence of excessive catecholamine production does not exclude the presence of manifestations of SDHD outside the head and neck region. These findings suggest that a more extensive imaging strategy in SDHD mutation carriers may be warranted for detection of biochemically silent lesions.