In this study, subtotal thymic material removed during operation for congenital heart disease and histological changes were investigated. Correlation of these changes with the type of the cardiac anomaly were also observed.

The study included 25 patients who were operated on between January and December 1997 at Dokuz Eylül University Faculty of medicine, Department of Thoracic and Cardiovascular Surgery. Eighteen of them (%72) were male and seven (18%) female and range of age was between 1 and 12 years (mean 5.5). Major cardiac anomalies were constituted by tetralogy of Fallot (TOF) in 11 cases (44%), ventricular septal defects in nine (36%), aortic stenosis in two, atriel septal defect in one and mitral regurgitation in one case. There was no syndrome which could be described as the cause of the congenital thymic defect. Morphological changes of thymic tissues related to the age of the patient and the type of the cardiac anomaly were compared with each other.

Starry sky appearance was revealed in the cortical layer in 16 cases (64%). Eight of these patients had the diagnosis of tetralogy of Fallot and six of them were VSD patients. Differentiation of Hassall corpuscles was detected in 12 patients, and nine of them had tetralogy of Fallot. Corticomedullary effacement disappeared in nine cases (6 TOF and 2 VSD). In children with cyanotic congenital heart defects, severe hypoxia and stress attacks, detection of histological findings suggestive of thymocyte apoptosis could give the evidence of its effects on cytological and consequently on humoral immunity.