Succinate Dehydrogenase B Subunit-Negative Jugular Foramen Paraganglioma Manifesting Malignant Progression with Pseudohypoxia-Related Atypical Uptake of [¹⁸F]-Fluoro-2-Deoxy-d-Glucose: A Case Report.

Abstract

Paragangliomas are generally benign, slow-growing tumors. However, approximately 10%-20% are malignant, characterized by distant metastasis. Recently, a germ line mutation in succinate dehydrogenase B subunit (SDHB) has been shown to be associated with malignant behavior in paraganglioma. Here we present a case of SDHB-negative malignant paraganglioma of the jugular foramen with a pseudohypoxic microenvironment and unique imaging features on [¹⁸F]-fluoro-2-deoxy-d-glucose positron emission tomography ([¹⁸F]-FDG PET), and discuss the significance of SDHB immunohistochemistry and the potential of [¹⁸F]-FDG PET for clinical management. A 55-year-old woman was diagnosed with jugular foramen paraganglioma. Initial surgical resection was performed; however, follow-up [¹⁸F]-FDG PET indicated multiple uptake regions throughout the body. Biopsies for multiple recurrent lesions revealed consistent pathological features, suggesting distant metastasis. Immunohistochemical analysis revealed a lack of SDHB immunostaining in all specimens. Pseudohypoxic markers, including hypoxia-inducible factor-1α and downstream glycolysis enzymes, were strongly expressed. [¹⁸F]-FDG PET demonstrated increased uptake in the lesions, and the patient died 3 years after initial metastasis. In patients with head and neck paraganglioma without SDHB expression, close follow-up should be considered because of the risk for metastasis. In such cases, [¹⁸F]-FDG PET might be useful for detecting metastasis due to atypical accumulation from pseudohypoxia-induced glycolysis.