Multiple cutaneous monoclonal B-cell proliferations as harbingers of systemic angioimmunoblastic T-cell lymphoma.

We describe a 66-year-old man initially diagnosed with primary cutaneous marginal zone B-cell lymphoma who developed four additional monoclonal/monotypic B-cell lymphoid proliferations and a systemic angioimmunoblastic T-cell lymphoma over the course of 19 months. Through retrospective analysis, we identified the evolution of a T-cell clone within the background of clinically and pathologically dominant cutaneous B-cell tumors. In terms of clinical practice, this case supports that patients diagnosed with multiple clonal B-cell proliferation need thorough investigation and close clinical follow up to identify a coexistent or evolving systemic lymphoma, in particular, peripheral T-cell lymphomas of follicular T-helper cell type, such as angioimmunoblastic T-cell lymphoma. Biologically, this case offers unique insight into the interactions between B-cell and T-cell lineages in lymphoid neoplasia.