Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasia of interdigitating dendritic cells. Two single case reports documenting IDCS harboring t(14;18) translocation involving immunoglobulin heavy chain (IGH) and BCL2 have been reported recently; however, one of the 2 IDCS has a synchronous follicular lymphoma, the absence or presence of a follicular lymphoma in the remaining case is not mentioned. In this study, by using polymerase chain reaction and fluorescence in situ hybridization techniques, we have showed that there is neither t(14;18)/IGH-BCL2 nor IGH gene rearrangement in 4 de novo IDCS without a concurrent or known history of a B-cell lymphoma, including follicular lymphoma, indicating that BCL2 chromosomal translocation is not a general feature of de novo IDCS.