Pizzi M, et al. - In this retrospective study, the researchers characterized the presence/distribution of benign TdT-positive cells in pediatric and adult reactive lymph nodes, as well as defined the phenotype and nature of such elements. For this analysis, 141 reactive lymph nodes from pediatric and adult patients without a history of neoplastic disease were considered. In pediatric and adult lymph nodes, TdT-positive cells were a common finding. Findings revealed that TdT positivity did not correlate with any clinical and histological parameter and double immunostaining disclosed a phenotype compatible with early lymphoid precursors. In all fetal lymph nodes, a very high TdT-positive cell density was reported.