Does "in situ lymphoma" occur as a distinct step in the development of nodular lymphocyte-predominant Hodgkin lymphoma?

Abstract

The concept of in situ neoplasia, already well acknowledged in epithelial tumors, has now been extended to lymphoid neoplasms. Among germinal center (GC)-derived lymphomas, a type of "in situ follicular lymphoma (FL)" has been described in which cells that strongly express BCL2 are observed in histologically abnormal follicles. In this commentary, the author suggests that another GC-derived lymphoma, ie, nodular lymphocyte-predominant Hodgkin lymphoma with a micronodular pattern in which small GCs or broken-up GCs are present within nodules, may be regarded as an early lesion limited to GC. Like "in situ FL," this is likely to be an in situ step that potentially leads to overt lymphoma.