How is the epidemiology of mediastinal diseases?

1/3 of neoplasms are malignant, ones affecting children are more likely to be malignant than those affecting adults Most masses (90%) are benign (asymptomatic), but 50% of symptomatic masses are malignant. 75% of pt with malignant neoplasms are symptomatic while less than 50% of ones with benign are symptomatic