Mediastinal Clear Cell Lymphoma-A Distinct Entity of B-Cell Derived Lymphoma as Shown by Immunotyping and Analysis of Gene Rearrangements.

Mediastinal clear cell lymphoma (MCCL) is regarded as a distinct subtype of Non-Hodgkin's-lymphoma. We have analyzed gene rearrangements of eight cases of newly diagnosed MCCL in order to verify their alignment to the B-cell lineage as suggested by immunotyping. The lymphoma cells shared a common immunophenotype which consisted of CD10-, CD19+, CD20+, and CD21-. Rearrangements of the heavy chain of the immunoglobulin gene were found in all eight cases studied. In contrast, the beta chain of the T-cell antigen receptor gene was not rearranged. No rearrangements of the kappa light chain gene were detected. There was no evidence for a t(14;18) or a t(8;14). In conclusion, MCCL seems to be a B-cell derived tumor, which is distinct from other known lymphomas both by its immunophenotype and genotype.