Abstract:

Objective To analyze the clinical characteristics and genetic phenotypes of children and adolescents with metastatic pheochromocytoma and paraganglioma (PPGL) at initial diagnosis and recurrence or metastasis. Methods A retrospective analysis was conducted on the clinical data, catecholamine levels, and genetic characteristics of 41 children and adolescents with metastatic PPGL at the initial diagnosis and after recurrence and metastasis, who were admitted to the hospital from January 2014 to October 2024. Results Hypertension was the most common manifestation at both the initial diagnosis (76.9%) and recurrence and metastasis (80.6%) of PPGL in children and adolescents. However, paroxysmal hypertension was more common at the initial diagnosis (56.7%), while persistent hypertension was more prevalent at recurrence and metastasis (80.0%), with a statistically significant difference (P=0.008). The incidence rates of headache, typical triad, nausea/vomiting, and fatigue were significantly different between the initial diagnosis and recurrence and metastasis stages (all P<0.05). Laboratory tests showed that abnormal urine catecholamines were most prominently characterized by elevated urine norepinephrine (NE) at both the initial diagnosis (86.5%) and recurrence and metastasis (90.3%), and the proportion of patients with two or more abnormal urine catecholamines was over 50% in both stages (54.1% and 54.8%, respectively). Lymph nodes were the most common site of recurrence and metastasis (68.3%), and 80.5% of the patients had two or more sites of recurrence and metastasis. 64.5% of the PPGL patients carried pathogenic gene variations, with SDHB mutations being the most common (45.2%). The median progression-free survival (PFS) of the group with clear gene variations was 42 months, significantly shorter than that of the group without detected gene variations (115 months), with a statistically significant difference (χ²=4.91, P=0.027). Conclusion Hypertension is the core manifestation of PPGL in children and adolescents at both the initial diagnosis and recurrence and metastasis stages, but the types of hypertension are significantly different. Recurrence and metastasis often present as multifocal and multi-site. Pathogenic gene variations may be related to the long-term prognosis of children, and further validation is needed through larger sample sizes and longer follow-up periods in future cohort studies.

Key words: pheochromocytoma, children and adolescents, clinical characteristics, genetic variations