Carotid Body Paraganglioma With an SDHD Gene Mutation: The Need For Genetic Testing

ABSTRACT Objective: To report a case of carotid body paraganglioma occurring in conjunction with a succinate dehydrogenase complex subunit D (SDHD) gene mutation with comorbidities of multiple retroperitoneal paragangliomas and pheochromocytoma. This case emphasizes the importance of performing genetic analyses in all cases of paragangliomas with carotid body involvement, multifocal origin, or concurrent pheochromocytoma to identify potential hereditary tumor susceptibility. We also emphasize the importance of familial screening of all first-degree family relatives of patients who test positive for germline mutations. Methods: A 30-year-old male underwent surgery to excise a carotid body tumor and multiple retroperitoneal masses and to perform a partial adrenalectomy. Results: Pathologic evaluation of carotid body and retroperitoneal specimens confirmed that they were histologically and immunohistochemically consistent with paragangliomas. The excised adrenal gland specimen tested positive for pheochromocytoma. The patient underwent genetic profiling and tested positive for an SDHD gene mutation. Conclusions: Carotid body paraganglioma is a rare but important differential diagnosis to consider when a young, hypertensive individual presents with unilateral neck swelling. The carotid body is the most common site of presentation for familial paragangliomas, which are frequently multifocal in origin. Genetic analysis to identify potential hereditary tumor susceptibility should be performed in all cases of paragangliomas with carotid body involvement, a multifocal origin, or concurrent pheochromocytoma. The SDHD gene is the most common gene associated with familial paragangliomas. Familial screening with genetic analysis should be encouraged for all first degree relatives of patients who test positive for SDHD germline mutations. Abbreviations: CT = computed tomography MIBG = metaiodobenzylguanidine MRI = magnetic resonance imaging SDHD = succinate dehydrogenase complex, subunit D