SAT547 Hereditary Paraganglioma: The Rare Co-Existence Of Two Genetic Syndromes Associated With PPGL-pheochromocytoma

Disclosure: K. Samuel: None. Hereditary Paraganglioma: the rare co-existence of two genetic syndromes associated with PPGL-Pheochromocytoma Kelara Samuel MD, Bryan McIver MD, Colleen Veloski MD, Julie Hallanger-Johnson MD, Valentina D. Tarasova, John Tourtelot MD, George Q. Yang MD, Sarimar Agosto-Salgado MD Background: Paragangliomas are neuroendocrine tumors arising from neural crest chromaffin cells of the autonomic ganglia and can be parasympathetic or sympathetic in nature. Approximately 30 percent of all paragangliomas are hereditary either associated with familial paraganglioma syndromes and other autosomal dominant syndromes, such as multiple neuroendocrine neoplasia 2A and 2B, neurofibromatosis type 1, and von Hippel Lindau disease.Case: A 73-year-old Hispanic female with a past medical history of hypothyroidism, hypertension, hyperlipidemia, and Lupus presented with a large neck mass of 11 years of evolution. An evaluation revealed a large near 12cm hypervascular, hyperenhancing left neck mass that encased the distal common carotid artery, carotid bifurcation, and internal and external carotid arteries and their branches. The multidisciplinary team recommended, given the tumor's extent, a non-surgical localized treatment consisting of radiation. Clinically, the patient had compressive symptoms, including tenderness over the tumor region, hoarseness, dysphagia, and changes in phonation. The patient also had a positive family history of paraganglioma in her grandson and nephew, but specific genetic alteration data from relatives was unavailable. Plasma normetanephrines were 0.68 (normal range 0-0.89), and plasma metanephrines were 0.23 (normal range 0-0.49). Genetic testing was positive for germline alterations in both SDHB p.Q214 and NF1 c.2970_2972delAAT. At this time, there is no evidence of metastatic disease and no clinical manifestations of NF1, suggesting a mild neurofibromatosis phenotype. Restaging imaging revealed an ongoing partial response to radiation and clinically patient has noted a significant improvement in the prior compressive symptoms. Conclusion: We present a case where we see an uncommon presentation of a non-secretory, hereditary paraganglioma with two concomitant rare genetic syndromes. This case highlights the importance of genetic testing for patient-appropriate tumor surveillance and family counseling implications. Presentation Date: Saturday, June 17, 2023