Endocrine Abstracts

JOINT3956

Background: Paraganglioma is a rare catecholamine secreting neuroendocrine tumour commonly occurring in the head and neck. They are usually slow growing and can be associated with genetic syndromes 35% of the cases. Treatment depends on the size and location of the tumour and if completely excised can have good prognosis. However, once metastasised, rapid progression and poor prognosis are observed. Here, were describe a rare case of germline pathogenic succinate dehydrogenase subunit B (SDHB) gene linked metastatic paraganglioma.

Case: A 42-year-old gentleman came into Emergency Department after he fell from a chair. MRI showed a pathological C3 collapse with tumour infiltration and enlarged jugular chain lymphadenopathy. He also had high blood pressure and upon detailed history complained of multitude of intermittent symptoms which he had ignored in the last 6 months (including chest pain, palpitations, somnolence, feeling sweaty, double vision and pins and needles in left arm). Initial biopsy after anterior C3 corpectomy showed osseous hemangioblastoma. Further biopsy of lymphadenopathy showed strong expression of inhibin and positive chromogranin and synaptophysin. MIBG and 68Ga PET scan revealed extensive metastasis from skull base into the pelvis involving cervical spine, skull base, left scapula, bilateral ribs, pelvis, bilateral para-aortic soft tissue and left liver lobe. Subsequent immunohistochemistry showed- low Ki-67 index, 1-2%. Bloods tests showed low plasma metanephrines (174.2 pmol/l (reference <510pmol/l)) and significantly raised plasma normetanephrines (30,508 pmol/l (reference <1180 pmol/l)). He was thus diagnosed with metastatic paraganglioma and treated under Endocrinology, Oncology, Neurosurgery and Ophthalmology. Genetic testing was positive for SDHB gene which was also positive in five of his other eight siblings. He was treated symptomatically with alpha-blockers and beta blockers, and received palliative surgery (e.g., for skull base/brain involvement), together with systemic treatment including treatment with CAPTEM chemotherapy, radiotherapy, and lutetium PRRT. Unfortunately, he passed away within 4 years of diagnosis.

Discussion: Metastatic paragangliomas are rare and challenging to treat due to often late presentation based on initially non-specific symptoms, often rapid spread, and limited treatment options. Patients with SDHB gene mutations have increased risk of developing metastases and hence require, long-term surveillance. Early diagnosis is crucial to ensure optimum management. Metastatic disease can be managed with options like radiotherapy, radiofrequency, chemotherapy or molecular targeted therapies like PRRT. Multidisciplinary team approach is central to treatment given its complex nature.