[Correlation of clinical, radiologic and pathologic aspects of the thymus in newborn infants]

The thymus of 30 autopsied neonates who died from different causes (hyaline membrane disease: 13 cases; severe infections: 11 cases; congenital malformations: 4 cases; severe asphyxia: 2 cases) were prospectively examined in order to look for the most frequent macroscopic and microscopic morphological changes in this organ. Findings were correlated with clinical and radiological data. In hyaline membrane disease patients moderate decrease of thymic weight and slight depletion of cortical lymphocytes as to reference values were observed; such changes were likewise seen in cases with malformations and severe asphyxia. Newborns who died from severe infections exhibited early and pronounced decrease of thymic weight as well as severe depletion of cortical lymphocytes, more noticeable at all times than in the remaining groups. It is concluded that the predominant finding in examined patients is thymic involution secondary to stress, whose intensity would depend upon the type and duration of the main disease, being most severe the longer the evolutionary time. The variability observed in thymic size of individuals with similar physical features and the lack of an accurate correlation between radiology and post mortem findings with respect to thymic size are remarkable.