Clinical Characteristics of Mediastinal Paragangliomas: A retrospective study

BACKGROUND: Studies focusing on mediastinal paragangliomas are limited. In this study, we describe the clinical, pathological, and genetic characteristics of mediastinal paragangliomas. METHODS: Clinical data from all patients with extrapericardial mediastinal paragangliomas at a single center were retrospectively analyzed. Germline variants were assessed using next-generation sequencing and Sanger sequencing of blood samples. Patients were grouped according to genetic variants and tumor location, and clinical characteristics were compared. RESULTS: 22 patients (male:female ratio, 8:14) were included in the study, with a mean age of 41.4 years. Hypertension was present in 16 patients (72.7%), and 13 (59.1%) exhibited typical catecholamine-related symptoms. Tumors were located in the anterior, middle, and posterior mediastinum in 1 (4.5%), 4 (18.2%), and 17 (77.3%) cases, with an average size of 5.3±1.7 cm. Multiple tumors were identified in 6 patients. Catecholamine-producing tumors were observed in 17/21 (81.0%) patients. Surgical resection was performed in 20 (90.9%) patients. No postoperative local recurrences were observed. Metastasis occurred in 2/18 (11.1%) cases. Eleven patients underwent genetic testing; six harbored SDHx mutations. Compared with anterior and middle mediastinal tumors, posterior mediastinal tumors were associated with higher rates of typical symptoms (12/17 vs. 1/5, p = 0.043) and catecholamine-producing function (17/17 vs. 0/4, p < 0.001), as well as higher levels of 24-hour urinary norepinephrine (5.10 × ULN vs. 0.56 × ULN, p = 0.037). CONCLUSION: Mediastinal paragangliomas are rare and are frequently associated with SDHx variants. Posterior mediastinal tumors are predominantly functional and noradrenergic; recognizing these features may facilitate diagnosis.