SUN-468 Radiographic Mimicry: A Case of an Incidental Paraganglioma First Diagnosed as a Renal Artery Aneurysm

Abstract Disclosure: K. Taquechel: None. P. Sinha: None. Background: Paragangliomas are rare neuroendocrine tumors that arise from autonomic paraganglioma and can potentially secrete excess catecholamines. Radiographic diagnosis of paragangliomas can present challenges as they often share features of other lesions including vascular malformations. Clinical Case: We present a case of a paraganglioma initially diagnosed as a renal artery aneurysm. A 55-year-old woman with a history of hypertension, multinodular goiter, and resected endometrial adenocarcinoma underwent a CT scan of the abdomen and pelvis for postmenopausal bleeding. She was incidentally found to have what appeared to be a right renal artery aneurysm and underwent endovascular stenting of the lesion. Five years later, she had a follow-up CT scan to evaluate the renal artery stent. The lesion originally thought to be an aneurysm had increased in size with new areas of heterogeneity. An MRI of the abdomen was thus performed, and imaging characteristics appeared consistent with a paraganglioma. She was referred to endocrinology. Blood testing was notable for an elevated plasma normetanephrine level (777 pg/mL) and chromogranin A (279 ng/mL). Urine testing showed an elevated normetanephrine level (1615 mcg/24h) and norepinephrine level (261 mcg/24h). She was pre-treated with doxazosin and metoprolol before undergoing successful resection of the paraganglioma and radical nephrectomy. Subsequently, her blood pressure improved and she required only one, rather than three antihypertensive agents. She also noted an improvement in mood and energy after surgery. Genetic testing was negative for any known mutations associated with paragangliomas. Conclusion: Paragangliomas can present a diagnostic challenge as they can resemble other lesions including, rarely, vascular malformations. To our knowledge, this case is the first to describe a paraganglioma mimicking a renal artery aneurysm. When such lesions demonstrate atypical characteristics (such as growth over time) rarer pathologies such as paragangliomas may need to be considered as they require a multidisciplinary approach for appropriate treatment. Reference: 1) Neumann, H. P. H., Young, W. F., & Eng, C. (2019). Pheochromocytoma and Paraganglioma. The New England Journal of Medicine, 381(6), 552-565. 2) Chow S, Chu R, Ho S, Chan A, Burd A. Paraganglioma Presenting as a Vascular Malformation: Case Report. Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. 2006;59(1):90-3. 3) Rajoo AR, Kannairan S, Habeebullah Khan HA, Md Idris MA, Tan GC, Chandra Sakaran KR, Safri LS. Case report: Paraganglioma masquerading as angiosarcoma: diagnostic-dilemma in vascular tumors. Front Oncol. 2024 Dec 5;14:1462956. Presentation: Sunday, July 13, 2025