Adrenal Tumors in Children and Adolescents in Sweden: A Register-Based Study Covering 15 Years.

Context: Adrenal tumors (ATs) are highly uncommon in children and adolescents, and more information on these tumors is needed.

Objective: The aim of this study was to describe the tumor incidence, patient and tumor characteristics, treatment, and mortality in pediatric patients with ATs.

Methods: This is a Swedish nationwide, register-based, retrospective study. All patients up to 21 years old diagnosed between 2005 and 2019 with an AT were identified through national registers and then manually reviewed. Age-, sex-, and municipality-matched controls in a ratio 4:1 were selected from the total population register.

Results: In total, 230 patients were included (and 920 controls), with an annual incidence of 6.20 new ATs per million for individuals up to 21 years old. The median age was 6.0 years (interquartile range, 1.0-17.70), with 120 (52.2%) being boys. Regarding tumor biology, 132 (57.4%) were malignant, 77 (33.5%) benign, and 21 (9.1%) were undetermined. There were at least 39 (16.9%) hormonally active ATs recognized as either pheochromocytomas, adrenocortical carcinomas, or benign functional adenomas. Patients with malignant tumors were younger than patients with benign tumors (mean age 2 vs 18, P < .001). Among patients with malignant ATs, the mortality reached 33.3% during a follow-up period of up to 15 years. Patients who were younger and received less aggressive treatments had better overall survival. Mortality was increased in all patients with malignant ATs compared to controls (P < .0001). Mortality was similar between patients with benign ATs and controls (P > .05).

Conclusion: Although rare, most identified tumors were malignant and associated with high mortality.