Endocrine Abstracts

SDHB mutations are associated with one of the most aggressive familial pheochromocytoma–paraganglioma syndromes (FPPS), characterized by a marked tendency for metastasis and poor prognosis. Emerging literature emphasizes that management strategies should be guided by molecular clusters of tumorigenesis, which define clinical, biochemical, radiological, and therapeutic behavior. We present the case of a 67-year-old man who initially reported long-standing, non-specific abdominal pain without red flag symptoms. With progressive worsening over several months, his general practitioner arranged an abdominal ultrasonography, which revealed multiple intra-abdominal masses involving both kidneys and the right para-aortic region. Subsequent PET-CT demonstrated moderate avidity in the right adrenal and left cervical regions. Biopsies confirmed a paraganglioma in the neck mass and bilateral renal oncocytomas. Plasma metanephrines were within normal limits. Genetic testing identified a heterozygous SDHB mutation. An attempted radical adrenalectomy was unsuccessful due to complex vascular anatomy, rendering the tumor inoperable. The patient subsequently received three sessions of 131I-MIBG therapy at a tertiary center, achieving borderline radiologic response without significant clinical improvement. He was later lost to follow-up and re-presented with worsening pain and functional decline. Repeat imaging demonstrated progressive disease with vascular invasion. Further MIBG therapy was recommended at the neuroendocrine tumor multidisciplinary team (NET MDT) meeting. However, as his main priority was pain relief and quality of life—and given the absence of meaningful clinical response to prior MIBG therapy—the appropriateness of this option was questioned, particularly in the context of his declining functional status. This case highlights the therapeutic challenges of managing locally aggressive, multicentric SDHB-related paragangliomas, particularly when first- and second-line therapies fail and functional status deteriorates. Although poor performance status can limit treatment options, evidence-based alternatives remain available that may reduce morbidity and improve quality of life.