There have been many different approaches to the classification of ILD, with major shifts based on clinical investigation, improvement in chest imaging, and collaboration with pathologists. In 1998, Katzenstein and Myers proposed four histopathologically distinct subgroups of idiopathic interstitial pneumonias: usual interstitial pneumonia (UIP), desquamative interstitial pneumonia (DIP) and a closely related pattern termed respiratory bronchiolitis-associated ILD, acute interstitial pneumonia (formerly Hamman-Rich syndrome), and non specific interstitial pneumonia (NSIP) [4] . In 2002, an international multidisciplinary consensus classification of idiopathic interstitial pneumonias was proposed by the American Thoracic Society (ATS)/European Respiratory Society (ERS) [5] . This classification defined a set of histologic pattern that provided the basis for clinico-radiologic-pathologic diagnosis, with the final pathologic diagnosis being made after careful correlation with clinical and radiologic features. However, as discussed in several reports, the classification schemes of adult ILD are not satisfactory for the pediatric cases which seem to comprise a broader spectrum of disorders with a more variable clinical course [6] . In addition, pediatric histologic patterns often do not resemble pathologic features of lung tissues from adults and some forms are only observed in children younger than 2 years.