[Clonal relationship of Hodgkin lymphoma and its recurrence]

In this study, we investigated whether recurrences of classical Hodgkin's lymphoma (HL) are true relapses arising from the primary tumour or clonally unrelated secondary neoplasias. Formalin-fixed, paraffin-embedded tissue specimens of eleven patients with recurrent HL were analyzed. Hodgkin and Reed-Sternberg cells were microdissected after immunohistochemical staining for CD30 using laser-capture technique. Immunoglobulin heavy chain (IgH) gene fragment lengths were analyzed applying consensus FR3 and J primers. Two early relapses after the first HL diagnosis were clonally related to the initial tumour, while three of four early recurrences after a first or second relapse were not. Three patients presenting with late relapses had clonally unrelated neoplasms. Therefore, we conclude that recurrent HL may represent a novel neoplasm, a finding which might play a role in clinical decision-making.