Characteristics of pediatric pheochromocytoma/paraganglioma

The "rule of 10" used to describe pheochromocytoma/paragangliomas (PCC/PGLs) has been challenged. However, recent studies suggested that pediatric PCC/PGLs may follow a pattern. Hence, we reviewed the available literature to verify the same. We searched PubMed, Scopus, ProQuest, and Google Scholar for studies describing the genotype and/or phenotype characteristics of pediatric PCC/PGL cohorts published after 2000 in English language and those with sample size more than 35 were included in this review. Pediatric PCC/PGLs were malignant in 10%, synchronous bilateral in 20%, extra-adrenal in 30%, among which, 30% were extra-abdominal and familial in 40%. PCC/PGL diagnosed during pediatric age recurs in 50% by 30 years of follow-up and 60% cases occur in boys. Seventy percent of children with PCC/PGL are likely to have sustained hypertension. Germline mutations could be identified in 80% of children with PCC/PGL and 90% are secretory. The review concludes that pediatric PCC/PGLs follow a pattern, which we call "10%-90% rule." This new rule will help easily remember the characteristics of pediatric PCC/PGLs.