A Rare Case of Metastatic Carotid Body Paraganglioma: A 7-Year Asymptomatic Period.

Paragangliomas are rare neuroendocrine tumors that arise from chromaffin cells that can be sympathetic or parasympathetic in nature. Paragangliomas are closely related to pheochromocytomas, which are also a form of neuroendocrine tumor arising from the adrenal medulla (Chen et al., 2010; García-Carbonero et al., 2021). Paragangliomas of sympathetic origin are often secretory in nature, causing symptoms such as headache, palpitations, excessive perspiration, and high blood pressure, and are most often found along the sympathetic chain. Common locations include the abdomen, skull base, bladder, and aortic bifurcation. Paragangliomas found in the head and neck region are often parasympathetic in origin and are non-functional. The annual incidence of paragangliomas varies from 0.04 to 0.9 individuals per 100,000 population (Subhi et al., 2022) and can present in any age group. The average age of diagnosis ranges from the third to fifth decade based on the nature of the tumor (Eisenhofer et al., 2011), and there is no significant gender predilection. These tumors are often associated with germline mutations in VHL, RET, NF1, SDHA,MEN2, SDHB, SDHC, SDHD, SDHAF2 genes (Timmers et al., 2007; Lefebvre and Foulkes, 2014; Fliedner et al., 2010). Most cases of paragangliomas are benign with very low potential for metastasis; overall, paragangliomas have a 0-36% chance of metastasis (Fliedner et al., 2010; O'Riordain et al., 1996) often being sympathetic in origin. Metastasis is more common in patients with a germline mutation in SDHB gene and having a primary tumor size greater than 5 cm at presentation (Araujo-Castro et al., 2023; Lam, 2017). This case highlights an unusual clinical course: a carotid body paraganglioma, initially asymptomatic and successfully resected, developed skeletal metastasis after a prolonged disease-free interval of 7 years. This report underscores the importance of revisiting conventional risk stratification, incorporating genetic testing, and ensuring vigilant, long-term follow-up.