8782 Rare presentation of a rapidly progressive metastatic paraganglioma in an elderly man

Abstract Disclosure: J. Haddad: None. G. Acosta: None. Background: Pheochromocytomas and paragangliomas (PPGLs) are endocrine tumors originating from neural crest-derived cells of the adrenal medulla or from the sympathetic or parasympathetic paraganglia. According to the World Health Organization classification, all PPGLs are considered to have metastatic potential. Treatment is challenging and a multidisciplinary approach is needed to manage such complex cases.Case: A 73-year-old male with a history of melanoma s/p resection, obstructive sleep apnea, left neck vagal paraganglioma s/p radiation therapy in 2011 and hypogonadism presents for evaluation of progressive hoarseness. Associated symptoms included vertigo, left facial numbness/tingling and left sided hearing loss. Physical examination revealed a red mass visible behind the tympanic membrane and a leftward tongue deviation. MRI showed rapid tumor growth in the jugular fossa with transcranial extension to the left cerebellar hemisphere concerning for tumor progression; of note, tumor size had been stable on serial neck imaging, last done one year prior. Plasma free metanephrines and 24-hour urine fractionated metanephrines were normal. The patient underwent intracranial tumor resection by neurosurgery, pathology consistent with paraganglioma; immunohistochemical staining showed loss of SDHB and next generation sequencing revealed a pathogenic variant of SDHC gene (SDHC p.M1V). At 6 months post-op, MRI scan showed stable size of residual tumor and evolving post-op changes. However, six months later, brain MRI showed growth of both intracranial and extracranial tumor components, compatible with disease progression. Ga-DOTATATE PET/CT scan showed avid uptake in left skull base (primary tumor) with extensive bony involvement in the spine, hips, sternum, ribs and left shoulder. Chromogranin A level was slightly elevated at 134.7 ng/mL (0.0 - 101.8 ng/mL) and repeat 24-hour urine fractionated metanephrines remained negative.The patient was initially prescribed octreotide and sunitinib; however, due to insurance issues, he was only able to receive one dose of octreotide. After multidisciplinary discussion between neuro-oncology, neurosurgery and endocrinology, decision was made to start systemic therapy with temozolomide and zoledronic acid. Given potential risk of catecholamine surge, alpha blockade therapy with doxazosin was recommended. Plan to monitor treatment response with Ga-DOTATATE PET/CT every 2 months. Conclusion: Metastatic paragangliomas pose diagnostic and therapeutic challenges, especially when exhibiting an aggressive behavior. A multidisciplinary approach is paramount in managing metastatic paragangliomas given the complex nature of this disease. Presentation: 6/3/2024