BACKGROUND. The Epstein-Barr virus (EBV) is thought to be involved in the pathogenesis of some Hodgkin disease (HD) cases. EBV may be associated particularly with childhood HD, a disease rare in the West compared with developing countries. In this study, a large series of Chinese pediatric HD cases has been examined to determine the age-specific prevalence of EBV. METHODS. Paraffin sections from 104 pediatric and 52 adult Chinese HD cases were examined for EBV-RNA (EBERs) and EBV latent membrane protein-1. RESULTS. Most pediatric cases arose in boys and showed an histology of mixed cellularity. Prominent interfollicular involvement was seen frequently in the childhood cases. EBV was identified in tumor cells in 113 of 156 (72%) HD cases but was more frequent in pediatric cases (93 of 104; 89%) compared with adult cases (20 of 52; 38%) (P < 0.01; chi-square test). EBV was found in 86 out of 91 (95%) cases in children aged 3-10 years and in 7 out of 13 (54%) cases in children aged 11-14 years (P < 0.01; chi-square test). The virus was less frequent in cases in young adults than in old adults, although this trend was not significant (P > 0.05; chi-square test). Pediatric HD was associated with EBV irrespective of histologic subtype. In adults, EBV was associated more frequently with mixed cellularity than with other subtypes. CONCLUSION. To the authors' knowledge, this is to date the largest series of pediatric HD cases studied for EBV. Study findings provided further evidence that HD is etiologically heterogenous. The authors believe that pediatric HD now should be regarded as a distinctive EBV-related lymphoma. (C) 2001 American Cancer Society.