A case of CD10-negative angioimmunoblastic T cell lymphoma with leukemic change and increased plasma cells mimicking plasma cell leukemia: A case report.

Angioimmunoblastic T cell lymphoma (AITL) is a peripheral T cell lymphoma, known to express CD3 and CD4, and, frequently, also CD10 and c-Maf-1. Hypergammaglobulinemia is not particularly rare in patients with AITL. However, AITL in conjunction with plasmacytosis in the peripheral blood is rare. The current report presents a case of CD10-negative AITL demonstrating leukemic change and plasmacytosis in the peripheral blood mimicking plasma cell leukemia. A 78-year-old male was admitted to hospital due to systemic lymph node enlargement, high serum IgG and IgA, and increased counts of plasmacytoid cells and lymphoid cells with atypical nuclei in the peripheral blood. Initially, plasma cell leukemia was suspected, due to the extreme increase in the number of plasma cells in the peripheral blood. However, the plasma cells did not show clonal expansion on examination by flow cytometry. Based on histological analyses, following a biopsy of an enlarged lymph node, the patient was diagnosed with AITL. This case suggests that when hypergammaglobulinemia and increases in B-lineage cells are observed, AITL should be considered in addition to disorders of B-lineage cells.